Use DN objects instead of strings

* Convert every string specifying a DN into a DN object

* Every place a dn was manipulated in some fashion it was replaced by
  the use of DN operators

* Add new DNParam parameter type for parameters which are DN's

* DN objects are used 100% of the time throughout the entire data
  pipeline whenever something is logically a dn.

* Many classes now enforce DN usage for their attributes which are
  dn's. This is implmented via ipautil.dn_attribute_property(). The
  only permitted types for a class attribute specified to be a DN are
  either None or a DN object.

* Require that every place a dn is used it must be a DN object.
  This translates into lot of::

    assert isinstance(dn, DN)

  sprinkled through out the code. Maintaining these asserts is
  valuable to preserve DN type enforcement. The asserts can be
  disabled in production.

  The goal of 100% DN usage 100% of the time has been realized, these
  asserts are meant to preserve that.

  The asserts also proved valuable in detecting functions which did
  not obey their function signatures, such as the baseldap pre and
  post callbacks.

* Moved ipalib.dn to ipapython.dn because DN class is shared with all
  components, not just the server which uses ipalib.

* All API's now accept DN's natively, no need to convert to str (or
  unicode).

* Removed ipalib.encoder and encode/decode decorators. Type conversion
  is now explicitly performed in each IPASimpleLDAPObject method which
  emulates a ldap.SimpleLDAPObject method.

* Entity & Entry classes now utilize DN's

* Removed __getattr__ in Entity & Entity clases. There were two
  problems with it. It presented synthetic Python object attributes
  based on the current LDAP data it contained. There is no way to
  validate synthetic attributes using code checkers, you can't search
  the code to find LDAP attribute accesses (because synthetic
  attriutes look like Python attributes instead of LDAP data) and
  error handling is circumscribed. Secondly __getattr__ was hiding
  Python internal methods which broke class semantics.

* Replace use of methods inherited from ldap.SimpleLDAPObject via
  IPAdmin class with IPAdmin methods. Directly using inherited methods
  was causing us to bypass IPA logic. Mostly this meant replacing the
  use of search_s() with getEntry() or getList(). Similarly direct
  access of the LDAP data in classes using IPAdmin were replaced with
  calls to getValue() or getValues().

* Objects returned by ldap2.find_entries() are now compatible with
  either the python-ldap access methodology or the Entity/Entry access
  methodology.

* All ldap operations now funnel through the common
  IPASimpleLDAPObject giving us a single location where we interface
  to python-ldap and perform conversions.

* The above 4 modifications means we've greatly reduced the
  proliferation of multiple inconsistent ways to perform LDAP
  operations. We are well on the way to having a single API in IPA for
  doing LDAP (a long range goal).

* All certificate subject bases are now DN's

* DN objects were enhanced thusly:
  - find, rfind, index, rindex, replace and insert methods were added
  - AVA, RDN and DN classes were refactored in immutable and mutable
    variants, the mutable variants are EditableAVA, EditableRDN and
    EditableDN. By default we use the immutable variants preserving
    important semantics. To edit a DN cast it to an EditableDN and
    cast it back to DN when done editing. These issues are fully
    described in other documentation.
  - first_key_match was removed
  - DN equalty comparison permits comparison to a basestring

* Fixed ldapupdate to work with DN's. This work included:
  - Enhance test_updates.py to do more checking after applying
    update. Add test for update_from_dict(). Convert code to use
    unittest classes.
  - Consolidated duplicate code.
  - Moved code which should have been in the class into the class.
  - Fix the handling of the 'deleteentry' update action. It's no longer
    necessary to supply fake attributes to make it work. Detect case
    where subsequent update applies a change to entry previously marked
    for deletetion. General clean-up and simplification of the
    'deleteentry' logic.
  - Rewrote a couple of functions to be clearer and more Pythonic.
  - Added documentation on the data structure being used.
  - Simplfy the use of update_from_dict()

* Removed all usage of get_schema() which was being called prior to
  accessing the .schema attribute of an object. If a class is using
  internal lazy loading as an optimization it's not right to require
  users of the interface to be aware of internal
  optimization's. schema is now a property and when the schema
  property is accessed it calls a private internal method to perform
  the lazy loading.

* Added SchemaCache class to cache the schema's from individual
  servers. This was done because of the observation we talk to
  different LDAP servers, each of which may have it's own
  schema. Previously we globally cached the schema from the first
  server we connected to and returned that schema in all contexts. The
  cache includes controls to invalidate it thus forcing a schema
  refresh.

* Schema caching is now senstive to the run time context. During
  install and upgrade the schema can change leading to errors due to
  out-of-date cached schema. The schema cache is refreshed in these
  contexts.

* We are aware of the LDAP syntax of all LDAP attributes. Every
  attribute returned from an LDAP operation is passed through a
  central table look-up based on it's LDAP syntax. The table key is
  the LDAP syntax it's value is a Python callable that returns a
  Python object matching the LDAP syntax. There are a handful of LDAP
  attributes whose syntax is historically incorrect
  (e.g. DistguishedNames that are defined as DirectoryStrings). The
  table driven conversion mechanism is augmented with a table of
  hard coded exceptions.

  Currently only the following conversions occur via the table:

  - dn's are converted to DN objects

  - binary objects are converted to Python str objects (IPA
    convention).

  - everything else is converted to unicode using UTF-8 decoding (IPA
    convention).

  However, now that the table driven conversion mechanism is in place
  it would be trivial to do things such as converting attributes
  which have LDAP integer syntax into a Python integer, etc.

* Expected values in the unit tests which are a DN no longer need to
  use lambda expressions to promote the returned value to a DN for
  equality comparison. The return value is automatically promoted to
  a DN. The lambda expressions have been removed making the code much
  simpler and easier to read.

* Add class level logging to a number of classes which did not support
  logging, less need for use of root_logger.

* Remove ipaserver/conn.py, it was unused.

* Consolidated duplicate code wherever it was found.

* Fixed many places that used string concatenation to form a new
  string rather than string formatting operators. This is necessary
  because string formatting converts it's arguments to a string prior
  to building the result string. You can't concatenate a string and a
  non-string.

* Simplify logic in rename_managed plugin. Use DN operators to edit
  dn's.

* The live version of ipa-ldap-updater did not generate a log file.
  The offline version did, now both do.

https://fedorahosted.org/freeipa/ticket/1670
https://fedorahosted.org/freeipa/ticket/1671
https://fedorahosted.org/freeipa/ticket/1672
https://fedorahosted.org/freeipa/ticket/1673
https://fedorahosted.org/freeipa/ticket/1674
https://fedorahosted.org/freeipa/ticket/1392
https://fedorahosted.org/freeipa/ticket/2872

25 files changed, 387 insertions, 192 deletions

diff --git a/ipalib/plugins/aci.py b/ipalib/plugins/aci.py
index 7a27ce116..7d5bf504c 100644
--- a/ipalib/plugins/aci.py
+++ b/ipalib/plugins/aci.py
@@ -123,24 +123,22 @@ from ipalib import api, crud, errors
 from ipalib import Object, Command
 from ipalib import Flag, Int, Str, StrEnum
 from ipalib.aci import ACI
-from ipalib.dn import DN
 from ipalib import output
 from ipalib import _, ngettext
 from ipalib.plugins.baseldap import gen_pkey_only_option
-if api.env.in_server and api.env.context in ['lite', 'server']:
-    from ldap import explode_dn
 from ipapython.ipa_log_manager import *
+from ipapython.dn import DN
 
 ACI_NAME_PREFIX_SEP = ":"
 
 _type_map = {
-    'user': 'ldap:///uid=*,%s,%s' % (api.env.container_user, api.env.basedn),
-    'group': 'ldap:///cn=*,%s,%s' % (api.env.container_group, api.env.basedn),
-    'host': 'ldap:///fqdn=*,%s,%s' % (api.env.container_host, api.env.basedn),
-    'hostgroup': 'ldap:///cn=*,%s,%s' % (api.env.container_hostgroup, api.env.basedn),
-    'service': 'ldap:///krbprincipalname=*,%s,%s' % (api.env.container_service, api.env.basedn),
-    'netgroup': 'ldap:///ipauniqueid=*,%s,%s' % (api.env.container_netgroup, api.env.basedn),
-    'dnsrecord': 'ldap:///idnsname=*,%s,%s' % (api.env.container_dns, api.env.basedn),
+    'user': 'ldap:///' + str(DN(('uid', '*'), api.env.container_user, api.env.basedn)),
+    'group': 'ldap:///' + str(DN(('cn', '*'), api.env.container_group, api.env.basedn)),
+    'host': 'ldap:///' + str(DN(('fqdn', '*'), api.env.container_host, api.env.basedn)),
+    'hostgroup': 'ldap:///' + str(DN(('cn', '*'), api.env.container_hostgroup, api.env.basedn)),
+    'service': 'ldap:///' + str(DN(('krbprincipalname', '*'), api.env.container_service, api.env.basedn)),
+    'netgroup': 'ldap:///' + str(DN(('ipauniqueid', '*'), api.env.container_netgroup, api.env.basedn)),
+    'dnsrecord': 'ldap:///' + str(DN(('idnsname', '*'), api.env.container_dns, api.env.basedn)),
 }
 
 _valid_permissions_values = [
@@ -247,7 +245,7 @@ def _make_aci(ldap, current, aciname, kw):
             if 'test' in kw and not kw.get('test'):
                 raise e
             else:
-                entry_attrs = {'dn': 'cn=%s,%s' % (kw['permission'], api.env.container_permission)}
+                entry_attrs = {'dn': DN(('cn', kw['permission']), api.env.container_permission)}
     elif group:
         # Not so friendly with groups. This will raise
         try:
@@ -343,10 +341,9 @@ def _aci_to_kw(ldap, a, test=False, pkey_only=False):
             else:
                 # See if the target is a group. If so we set the
                 # targetgroup attr, otherwise we consider it a subtree
-                if api.env.container_group in target:
-                    targetdn = unicode(target.replace('ldap:///',''))
-                    target = DN(targetdn)
-                    kw['targetgroup'] = target['cn']
+                targetdn = DN(target.replace('ldap:///',''))
+                if targetdn.endswith(DN(api.env.container_group, api.env.basedn)):
+                    kw['targetgroup'] = targetdn[0]['cn']
                 else:
                     kw['subtree'] = unicode(target)
 
@@ -357,15 +354,16 @@ def _aci_to_kw(ldap, a, test=False, pkey_only=False):
     elif groupdn == 'anyone':
         pass
     else:
-        if groupdn.startswith('cn='):
-            dn = ''
+        groupdn = DN(groupdn)
+        if len(groupdn) and groupdn[0].attr == 'cn':
+            dn = DN()
             entry_attrs = {}
             try:
                 (dn, entry_attrs) = ldap.get_entry(groupdn, ['cn'])
             except errors.NotFound, e:
                 # FIXME, use real name here
                 if test:
-                    dn = 'cn=%s,%s' % ('test', api.env.container_permission)
+                    dn = DN(('cn', 'test'), api.env.container_permission)
                     entry_attrs = {'cn': [u'test']}
             if api.env.container_permission in dn:
                 kw['permission'] = entry_attrs['cn'][0]
@@ -801,11 +799,11 @@ class aci_find(crud.Search):
         if kw.get('group'):
             for a in acis:
                 groupdn = a.bindrule['expression']
-                groupdn = groupdn.replace('ldap:///','')
-                cn = None
-                if groupdn.startswith('cn='):
-                    cn = explode_dn(groupdn)[0]
-                    cn = cn.replace('cn=','')
+                groupdn = DN(groupdn.replace('ldap:///',''))
+                try:
+                    cn = groupdn[0]['cn'].value
+                except (IndexError, KeyError):
+                    cn = None
                 if cn is None or cn != kw['group']:
                     try:
                         results.remove(a)
@@ -818,9 +816,11 @@ class aci_find(crud.Search):
                 if 'target' in a.target:
                     target = a.target['target']['expression']
                     if api.env.container_group in target:
-                        targetdn = unicode(target.replace('ldap:///',''))
-                        cn = explode_dn(targetdn)[0]
-                        cn = cn.replace('cn=','')
+                        targetdn = DN(target.replace('ldap:///',''))
+                        try:
+                            cn = targetdn[0]['cn']
+                        except (IndexError, KeyError):
+                            cn = None
                         if cn == kw['targetgroup']:
                             found = True
                 if not found:
diff --git a/ipalib/plugins/automember.py b/ipalib/plugins/automember.py
index 7ccb0bb2f..40359604b 100644
--- a/ipalib/plugins/automember.py
+++ b/ipalib/plugins/automember.py
@@ -22,8 +22,8 @@ from ipalib import Str, StrEnum
 from ipalib.plugins.baseldap import *
 from ipalib import _, ngettext
 from ipalib.request import context
-from ipalib.dn import *
 import ldap as _ldap
+from ipapython.dn import DN
 
 __doc__ = _("""
 Auto Membership Rule.
@@ -200,19 +200,16 @@ class automember(LDAPObject):
             parent_dn = self.container_dn
         grouptype = options['type']
         try:
-            ndn = DN(('cn', keys[-1]), ('cn', grouptype), DN(parent_dn))
+            ndn = DN(('cn', keys[-1]), ('cn', grouptype), parent_dn)
         except IndexError:
-            ndn = DN(('cn', grouptype), DN(parent_dn))
-        parent_dn = str(ndn)
-        return parent_dn
+            ndn = DN(('cn', grouptype), parent_dn)
+        return ndn
 
     def check_attr(self, attr):
         """
         Verify that the user supplied key is a valid attribute in the schema
         """
         ldap = self.api.Backend.ldap2
-        if not ldap.schema:
-            ldap.get_schema()
         obj = ldap.schema.get_obj(_ldap.schema.AttributeType, attr)
         if obj is not None:
             return obj
@@ -238,6 +235,7 @@ class automember_add(LDAPCreate):
     msg_summary = _('Added automember rule "%(value)s"')
 
     def pre_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
 
         entry_attrs['cn'] = keys[-1]
         if not automember_container_exists(self.api.Backend.ldap2):
@@ -284,6 +282,7 @@ class automember_add_condition(LDAPUpdate):
     )
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         # Check to see if the automember rule exists
         try:
             (tdn, test_attrs) = ldap.get_entry(dn, [])
@@ -370,6 +369,7 @@ class automember_remove_condition(LDAPUpdate):
     )
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         # Check to see if the automember rule exists
         try:
             (tdn, test_attrs) = ldap.get_entry(dn, [])
@@ -479,10 +479,10 @@ class automember_find(LDAPSearch):
     )
 
     def pre_callback(self, ldap, filters, attrs_list, base_dn, scope, *args, **options):
+        assert isinstance(base_dn, DN)
         scope = ldap.SCOPE_SUBTREE
-        ndn = DN(('cn', options['type']), DN(base_dn))
-        base_dn = str(ndn)
-        return (filters, base_dn, scope)
+        ndn = DN(('cn', options['type']), base_dn)
+        return (filters, ndn, scope)
 
 api.register(automember_find)
 
@@ -520,7 +520,6 @@ class automember_default_group_set(LDAPUpdate):
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
         dn = DN(('cn', options['type']), api.env.container_automember)
-        dn = str(dn)
         entry_attrs['automemberdefaultgroup'] = self.obj.dn_exists(options['type'], options['automemberdefaultgroup'])
         return dn
 
@@ -542,7 +541,6 @@ class automember_default_group_remove(LDAPUpdate):
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
         dn = DN(('cn', options['type']), api.env.container_automember)
-        dn = str(dn)
         attr = 'automemberdefaultgroup'
 
         (dn, entry_attrs_) = ldap.get_entry(
@@ -556,6 +554,7 @@ class automember_default_group_remove(LDAPUpdate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         if 'automemberdefaultgroup' not in entry_attrs:
             entry_attrs['automemberdefaultgroup'] = unicode(_('No default (fallback) group set'))
         return dn
@@ -576,10 +575,10 @@ class automember_default_group_show(LDAPRetrieve):
 
     def pre_callback(self, ldap, dn, attrs_list, *keys, **options):
         dn = DN(('cn', options['type']), api.env.container_automember)
-        dn = str(dn)
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         if 'automemberdefaultgroup' not in entry_attrs:
             entry_attrs['automemberdefaultgroup'] = unicode(_('No default (fallback) group set'))
         return dn
diff --git a/ipalib/plugins/automount.py b/ipalib/plugins/automount.py
index 5c9f42b4c..8e9eb5745 100644
--- a/ipalib/plugins/automount.py
+++ b/ipalib/plugins/automount.py
@@ -227,6 +227,7 @@ class automountlocation_add(LDAPCreate):
     msg_summary = _('Added automount location "%(value)s"')
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         # create auto.master for the new location
         self.api.Command['automountmap_add'](keys[-1], u'auto.master')
 
@@ -595,6 +596,7 @@ class automountmap_del(LDAPDelete):
     msg_summary = _('Deleted automount map "%(value)s"')
 
     def post_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         # delete optional parental connection (direct maps may not have this)
         try:
             (dn_, entry_attrs) = ldap.find_entry_by_attr(
@@ -718,7 +720,7 @@ class automountkey(LDAPObject):
                     (kwargs['automountkey'], kwargs['automountinformation'])
             else:
                 sfilter = '(automountkey=%s)' % kwargs['automountkey']
-            basedn = 'automountmapname=%s,cn=%s,%s' % (parent_keys[1], parent_keys[0], self.container_dn)
+            basedn = DN(('automountmapname', parent_keys[1]), ('cn', parent_keys[0]), self.container_dn)
             attrs_list = ['*']
             (entries, truncated) = ldap.find_entries(sfilter, attrs_list,
                 basedn, _ldap.SCOPE_ONELEVEL)
@@ -790,6 +792,7 @@ class automountkey_add(LDAPCreate):
     internal_options = ['description', 'add_operation']
 
     def pre_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         options.pop('add_operation', None)
         options.pop('description', None)
         self.obj.check_key_uniqueness(keys[-2], keys[-1], **options)
@@ -926,6 +929,7 @@ class automountkey_mod(LDAPUpdate):
             yield key
 
     def pre_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         if 'newautomountkey' in options:
             entry_attrs['automountkey'] = options['newautomountkey']
         if 'newautomountinformation' in options:
diff --git a/ipalib/plugins/baseldap.py b/ipalib/plugins/baseldap.py
index 32dae5160..e05f59ff4 100644
--- a/ipalib/plugins/baseldap.py
+++ b/ipalib/plugins/baseldap.py
@@ -34,7 +34,7 @@ from ipalib.cli import to_cli, from_cli
 from ipalib import output
 from ipalib.text import _
 from ipalib.util import json_serialize, validate_hostname
-from ipalib.dn import *
+from ipapython.dn import DN, RDN
 
 global_output_params = (
     Flag('has_password',
@@ -200,6 +200,7 @@ def validate_attribute(ugettext, name, attr):
         raise errors.ValidationError(name=name, error='Invalid format. Should be name=value')
 
 def get_effective_rights(ldap, dn, attrs=None):
+    assert isinstance(dn, DN)
     if attrs is None:
         attrs = ['*', 'nsaccountlock', 'cospriority']
     rights = ldap.get_effective_rights(dn, attrs)
@@ -332,6 +333,7 @@ def add_external_pre_callback(membertype, ldap, dn, keys, options):
 
     membertype is the type of member
     """
+    assert isinstance(dn, DN)
     # validate hostname with allowed underscore characters, non-fqdn
     # hostnames are allowed
     def validate_host(hostname):
@@ -361,12 +363,14 @@ def add_external_post_callback(memberattr, membertype, externalattr, ldap, compl
     membertype is the type of member: user,
     externalattr is one of externaluser,
     """
+    assert isinstance(dn, DN)
     completed_external = 0
     normalize = options.get('external_callback_normalize', True)
     # Sift through the failures. We assume that these are all
     # entries that aren't stored in IPA, aka external entries.
     if memberattr in failed and membertype in failed[memberattr]:
         (dn, entry_attrs_) = ldap.get_entry(dn, [externalattr])
+        assert isinstance(dn, DN)
         members = entry_attrs.get(memberattr, [])
         external_entries = entry_attrs_.get(externalattr, [])
         lc_external_entries = set(e.lower() for e in external_entries)
@@ -374,6 +378,7 @@ def add_external_post_callback(memberattr, membertype, externalattr, ldap, compl
         for entry in failed[memberattr][membertype]:
             membername = entry[0].lower()
             member_dn = api.Object[membertype].get_dn(membername)
+            assert isinstance(member_dn, DN)
             if (membername not in lc_external_entries and
                 member_dn not in members):
                 # Not an IPA entry, assume external
@@ -406,6 +411,7 @@ def add_external_post_callback(memberattr, membertype, externalattr, ldap, compl
     return (completed + completed_external, dn)
 
 def remove_external_post_callback(memberattr, membertype, externalattr, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+    assert isinstance(dn, DN)
     # Run through the failures and gracefully remove any member defined
     # as an external member.
     if memberattr in failed and membertype in failed[memberattr]:
@@ -440,7 +446,7 @@ def host_is_master(ldap, fqdn):
 
     Raises an exception if a master, otherwise returns nothing.
     """
-    master_dn = str(DN('cn=%s' % fqdn, 'cn=masters,cn=ipa,cn=etc', api.env.basedn))
+    master_dn = DN(('cn', fqdn), ('cn', 'masters'), ('cn', 'ipa'), ('cn', 'etc'), api.env.basedn)
     try:
         (dn, entry_attrs) = ldap.get_entry(master_dn, ['objectclass'])
         raise errors.ValidationError(name='hostname', error=_('An IPA master host cannot be deleted or disabled'))
@@ -518,9 +524,11 @@ class LDAPObject(Object):
             return self.backend.make_dn_from_attr(
                 self.primary_key.name, keys[-1], parent_dn
             )
+        assert isinstance(parent_dn, DN)
         return parent_dn
 
     def get_primary_key_from_dn(self, dn):
+        assert isinstance(dn, DN)
         try:
             if self.rdn_attribute:
                 (dn, entry_attrs) = self.backend.get_entry(
@@ -532,8 +540,6 @@ class LDAPObject(Object):
                     return ''
         except errors.NotFound:
             pass
-        # DN object assures we're returning a decoded (unescaped) value
-        dn = DN(dn)
         try:
             return dn[self.primary_key.name]
         except KeyError:
@@ -567,7 +573,7 @@ class LDAPObject(Object):
             for member in entry_attrs.setdefault(attr, []):
                 for ldap_obj_name in self.attribute_members[attr]:
                     ldap_obj = self.api.Object[ldap_obj_name]
-                    if member.find(ldap_obj.container_dn) > 0:
+                    if ldap_obj.container_dn in member:
                         new_attr = '%s_%s' % (attr, ldap_obj.name)
                         entry_attrs.setdefault(new_attr, []).append(
                             ldap_obj.get_primary_key_from_dn(member)
@@ -623,7 +629,6 @@ class LDAPObject(Object):
 
     def __json__(self):
         ldap = self.backend
-        ldap.get_schema()
         json_dict = dict(
             (a, getattr(self, a)) for a in self.json_friendly_attributes
         )
@@ -777,52 +782,47 @@ last, after all sets and adds."""),
 
     _callback_registry = dict(pre={}, post={}, exc={}, interactive_prompt={})
 
-    def _convert_2_dict(self, attrs):
+    def _convert_2_dict(self, ldap, attrs):
         """
         Convert a string in the form of name/value pairs into a dictionary.
 
         :param attrs: A list of name/value pair strings, in the "name=value"
             format. May also be a single string, or None.
         """
-        if attrs is None:
-            return {}
-
-        if not isinstance(attrs, (tuple, list)):
-            attrs = [attrs]
 
         newdict = {}
+        if attrs is None:
+            attrs = []
+        elif not type(attrs) in (list, tuple):
+            attrs = [attrs]
         for a in attrs:
-            m = re.match("^\s*(?P<attr>.*?)\s*=\s*(?P<value>.*?)\s*$", a)
-            attr = str(m.group('attr').lower())
-            value = m.group('value')
-
+            m = re.match("\s*(.*?)\s*=\s*(.*?)\s*$", a)
+            attr = str(m.group(1)).lower()
+            value = m.group(2)
             if attr in self.obj.params and attr not in self.params:
                 # The attribute is managed by IPA, but it didn't get cloned
                 # to the command. This happens with no_update/no_create attrs.
                 raise errors.ValidationError(
                     name=attr, error=_('attribute is not configurable'))
+            if len(value) == 0:
+                # None means "delete this attribute"
+                value = None
 
-            newdict.setdefault(attr, []).append(value)
+            if ldap.has_dn_syntax(attr):
+                value = DN(value)
 
+            if attr in newdict:
+                if type(value) in (tuple,):
+                    newdict[attr] += list(value)
+                else:
+                    newdict[attr].append(value)
+            else:
+                if type(value) in (tuple,):
+                    newdict[attr] = list(value)
+                else:
+                    newdict[attr] = [value]
         return newdict
 
-    def _convert_entry(self, entry_attrs):
-        result = {}
-        for attr, val in entry_attrs.iteritems():
-            if val is None:
-                val = []
-            elif not isinstance(val, (tuple, list)):
-                val = [val]
-
-            result[attr] = []
-            for v in val:
-                if isinstance(v, str):
-                    # This is a Binary value, base64 encode it
-                    v = base64.b64encode(v)
-                result[attr].append(unicode(v))
-
-        return result
-
     def process_attr_options(self, entry_attrs, dn, keys, options):
         """
         Process all --setattr, --addattr, and --delattr options and add the
@@ -847,14 +847,15 @@ last, after all sets and adds."""),
         :param keys: List of command arguments
         :param options: List of options
         """
+
         if all(k not in options for k in ("setattr", "addattr", "delattr")):
             return
 
         ldap = self.obj.backend
 
-        adddict = self._convert_2_dict(options.get('addattr', []))
-        setdict = self._convert_2_dict(options.get('setattr', []))
-        deldict = self._convert_2_dict(options.get('delattr', []))
+        adddict = self._convert_2_dict(ldap, options.get('addattr', []))
+        setdict = self._convert_2_dict(ldap, options.get('setattr', []))
+        deldict = self._convert_2_dict(ldap, options.get('delattr', []))
 
         setattrs = set(setdict.keys())
         addattrs = set(adddict.keys())
@@ -865,24 +866,24 @@ last, after all sets and adds."""),
             direct_del = delattrs
             needldapattrs = []
         else:
+            assert isinstance(dn, DN)
             direct_add = setattrs & addattrs
             direct_del = setattrs & delattrs
             needldapattrs = list((addattrs | delattrs) - setattrs)
 
-        mod_attrs = self._convert_entry(entry_attrs)
-
         for attr, val in setdict.iteritems():
-            mod_attrs[attr] = val
+            entry_attrs[attr] = val
 
         for attr in direct_add:
-            mod_attrs.setdefault(attr, []).extend(adddict[attr])
+            entry_attrs.setdefault(attr, []).extend(adddict[attr])
 
         for attr in direct_del:
             for delval in deldict[attr]:
                 try:
-                    mod_attrs[attr].remove(delval)
+                    entry_attrs[attr].remove(delval)
                 except ValueError:
-                    raise errors.AttrValueNotFound(attr=attr, value=delval)
+                    raise errors.AttrValueNotFound(attr=attr,
+                                                   value=delval)
 
         if needldapattrs:
             try:
@@ -901,27 +902,28 @@ last, after all sets and adds."""),
                 raise errors.ValidationError(name=del_nonexisting.pop(),
                     error=_('No such attribute on this entry'))
 
-            old_entry = self._convert_entry(old_entry)
-
             for attr in needldapattrs:
-                mod_attrs[attr] = old_entry.get(attr, [])
+                entry_attrs[attr] = old_entry.get(attr, [])
 
                 if attr in addattrs:
-                    mod_attrs[attr].extend(adddict.get(attr, []))
+                    entry_attrs[attr].extend(adddict.get(attr, []))
 
                 for delval in deldict.get(attr, []):
                     try:
-                        mod_attrs[attr].remove(delval)
+                        entry_attrs[attr].remove(delval)
                     except ValueError:
+                        if isinstance(delval, str):
+                            # This is a Binary value, base64 encode it
+                            delval = unicode(base64.b64encode(delval))
                         raise errors.AttrValueNotFound(attr=attr, value=delval)
 
         # normalize all values
         changedattrs = setattrs | addattrs | delattrs
         for attr in changedattrs:
-            value = mod_attrs[attr]
             if attr in self.params and self.params[attr].attribute:
-                param = self.params[attr]
                 # convert single-value params to scalars
+                param = self.params[attr]
+                value = entry_attrs[attr]
                 if not param.multivalue:
                     if len(value) == 1:
                         value = value[0]
@@ -931,19 +933,19 @@ last, after all sets and adds."""),
                         raise errors.OnlyOneValueAllowed(attr=attr)
                 # validate, convert and encode params
                 try:
-                    value = param(value)
+                   value = param(value)
                 except errors.ValidationError, err:
                     raise errors.ValidationError(name=attr, error=err.error)
                 except errors.ConversionError, err:
                     raise errors.ConversionError(name=attr, error=err.error)
+                entry_attrs[attr] = value
             else:
                 # unknown attribute: remove duplicite and invalid values
-                value = list(set([val for val in value if val]))
-                if not value:
-                    value = None
-                elif isinstance(value, (tuple, list)) and len(value) == 1:
-                    value = value[0]
-            entry_attrs[attr] = value
+                entry_attrs[attr] = list(set([val for val in entry_attrs[attr] if val]))
+                if not entry_attrs[attr]:
+                    entry_attrs[attr] = None
+                elif isinstance(entry_attrs[attr], (tuple, list)) and len(entry_attrs[attr]) == 1:
+                    entry_attrs[attr] = entry_attrs[attr][0]
 
     @classmethod
     def register_pre_callback(cls, callback, first=False):
@@ -1021,8 +1023,13 @@ class LDAPCreate(BaseLDAPCommand, crud.Create):
             entry_attrs[self.obj.uuid_attribute] = 'autogenerate'
 
         dn = self.obj.get_dn(*keys, **options)
+        assert isinstance(dn, DN)
         if self.obj.rdn_attribute:
-            if not dn.startswith('%s=' % self.obj.primary_key.name):
+            try:
+                dn_attr = dn[0].attr
+            except (IndexError, KeyError):
+                dn_attr = None
+            if dn_attr != self.obj.primary_key.name:
                 self.obj.handle_duplicate_entry(*keys)
             dn = ldap.make_dn(
                 entry_attrs, self.obj.rdn_attribute, self.obj.container_dn
@@ -1038,9 +1045,9 @@ class LDAPCreate(BaseLDAPCommand, crud.Create):
         for callback in self.get_callbacks('pre'):
             dn = callback(
                 self, ldap, dn, entry_attrs, attrs_list, *keys, **options)
+            assert isinstance(dn, DN)
 
         _check_single_value_attrs(self.params, entry_attrs)
-        ldap.get_schema()
         _check_limit_object_class(self.api.Backend.ldap2.schema.attribute_types(self.obj.limit_object_classes), entry_attrs.keys(), allow_only=True)
         _check_limit_object_class(self.api.Backend.ldap2.schema.attribute_types(self.obj.disallow_object_classes), entry_attrs.keys(), allow_only=False)
 
@@ -1074,16 +1081,19 @@ class LDAPCreate(BaseLDAPCommand, crud.Create):
                     self.obj.primary_key.name, keys[-1], object_class, attrs_list,
                     self.obj.container_dn
                 )
+                assert isinstance(dn, DN)
             else:
                 (dn, entry_attrs) = self._exc_wrapper(keys, options, ldap.get_entry)(
                     dn, attrs_list, normalize=self.obj.normalize_dn
                 )
+                assert isinstance(dn, DN)
         except errors.NotFound:
             self.obj.handle_not_found(*keys)
 
         for callback in self.get_callbacks('post'):
             dn = callback(self, ldap, dn, entry_attrs, *keys, **options)
 
+        assert isinstance(dn, DN)
         entry_attrs['dn'] = dn
 
         self.obj.convert_attribute_members(entry_attrs, *keys, **options)
@@ -1092,9 +1102,11 @@ class LDAPCreate(BaseLDAPCommand, crud.Create):
         return dict(result=entry_attrs, value=u'')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return dn
 
     def exc_callback(self, keys, options, exc, call_func, *call_args, **call_kwargs):
@@ -1181,6 +1193,7 @@ class LDAPRetrieve(LDAPQuery):
         ldap = self.obj.backend
 
         dn = self.obj.get_dn(*keys, **options)
+        assert isinstance(dn, DN)
 
         if options.get('all', False):
             attrs_list = ['*'] + self.obj.default_attributes
@@ -1189,11 +1202,13 @@ class LDAPRetrieve(LDAPQuery):
 
         for callback in self.get_callbacks('pre'):
             dn = callback(self, ldap, dn, attrs_list, *keys, **options)
+            assert isinstance(dn, DN)
 
         try:
             (dn, entry_attrs) = self._exc_wrapper(keys, options, ldap.get_entry)(
                 dn, attrs_list, normalize=self.obj.normalize_dn
             )
+            assert isinstance(dn, DN)
         except errors.NotFound:
             self.obj.handle_not_found(*keys)
 
@@ -1202,17 +1217,21 @@ class LDAPRetrieve(LDAPQuery):
 
         for callback in self.get_callbacks('post'):
             dn = callback(self, ldap, dn, entry_attrs, *keys, **options)
+            assert isinstance(dn, DN)
 
         self.obj.convert_attribute_members(entry_attrs, *keys, **options)
+        assert isinstance(dn, DN)
         entry_attrs['dn'] = dn
         if self.obj.primary_key and keys[-1] is not None:
             return dict(result=entry_attrs, value=keys[-1])
         return dict(result=entry_attrs, value=u'')
 
     def pre_callback(self, ldap, dn, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return dn
 
     def exc_callback(self, keys, options, exc, call_func, *call_args, **call_kwargs):
@@ -1261,6 +1280,7 @@ class LDAPUpdate(LDAPQuery, crud.Update):
             raise errors.EmptyModlist()
 
         dn = self.obj.get_dn(*keys, **options)
+        assert isinstance(dn, DN)
 
         entry_attrs = self.args_options_2_entry(**options)
 
@@ -1279,8 +1299,8 @@ class LDAPUpdate(LDAPQuery, crud.Update):
         for callback in self.get_callbacks('pre'):
             dn = callback(
                 self, ldap, dn, entry_attrs, attrs_list, *keys, **options)
+            assert isinstance(dn, DN)
 
-        ldap.get_schema()
         _check_limit_object_class(self.api.Backend.ldap2.schema.attribute_types(self.obj.limit_object_classes), entry_attrs.keys(), allow_only=True)
         _check_limit_object_class(self.api.Backend.ldap2.schema.attribute_types(self.obj.disallow_object_classes), entry_attrs.keys(), allow_only=False)
 
@@ -1294,10 +1314,10 @@ class LDAPUpdate(LDAPQuery, crud.Update):
             if self.obj.rdn_is_primary_key and self.obj.primary_key.name in entry_attrs:
                 # RDN change
                 self._exc_wrapper(keys, options, ldap.update_entry_rdn)(dn,
-                    unicode('%s=%s' % (self.obj.primary_key.name,
-                    entry_attrs[self.obj.primary_key.name])))
+                    RDN((self.obj.primary_key.name, entry_attrs[self.obj.primary_key.name])))
                 rdnkeys = keys[:-1] + (entry_attrs[self.obj.primary_key.name], )
                 dn = self.obj.get_dn(*rdnkeys)
+                assert isinstance(dn, DN)
                 del entry_attrs[self.obj.primary_key.name]
                 options['rdnupdate'] = True
                 rdnupdate = True
@@ -1306,6 +1326,7 @@ class LDAPUpdate(LDAPQuery, crud.Update):
             # to decide what to do. An EmptyModlist in this context doesn't
             # mean an error occurred, just that there were no other updates to
             # perform.
+            assert isinstance(dn, DN)
             self._exc_wrapper(keys, options, ldap.update_entry)(dn, entry_attrs, normalize=self.obj.normalize_dn)
         except errors.EmptyModlist, e:
             if not rdnupdate:
@@ -1327,6 +1348,7 @@ class LDAPUpdate(LDAPQuery, crud.Update):
 
         for callback in self.get_callbacks('post'):
             dn = callback(self, ldap, dn, entry_attrs, *keys, **options)
+            assert isinstance(dn, DN)
 
         self.obj.convert_attribute_members(entry_attrs, *keys, **options)
         if self.obj.primary_key and keys[-1] is not None:
@@ -1334,9 +1356,11 @@ class LDAPUpdate(LDAPQuery, crud.Update):
         return dict(result=entry_attrs, value=u'')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return dn
 
     def exc_callback(self, keys, options, exc, call_func, *call_args, **call_kwargs):
@@ -1360,11 +1384,14 @@ class LDAPDelete(LDAPMultiQuery):
         def delete_entry(pkey):
             nkeys = keys[:-1] + (pkey, )
             dn = self.obj.get_dn(*nkeys, **options)
+            assert isinstance(dn, DN)
 
             for callback in self.get_callbacks('pre'):
                 dn = callback(self, ldap, dn, *nkeys, **options)
+                assert isinstance(dn, DN)
 
             def delete_subtree(base_dn):
+                assert isinstance(base_dn, DN)
                 truncated = True
                 while truncated:
                     try:
@@ -1412,9 +1439,11 @@ class LDAPDelete(LDAPMultiQuery):
         return dict(result=dict(failed=u''), value=u'')
 
     def pre_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         return dn
 
     def post_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         return True
 
     def exc_callback(self, keys, options, exc, call_func, *call_args, **call_kwargs):
@@ -1495,14 +1524,17 @@ class LDAPAddMember(LDAPModMember):
         (member_dns, failed) = self.get_member_dns(**options)
 
         dn = self.obj.get_dn(*keys, **options)
+        assert isinstance(dn, DN)
 
         for callback in self.get_callbacks('pre'):
             dn = callback(self, ldap, dn, member_dns, failed, *keys, **options)
+            assert isinstance(dn, DN)
 
         completed = 0
         for (attr, objs) in member_dns.iteritems():
             for ldap_obj_name in objs:
                 for m_dn in member_dns[attr][ldap_obj_name]:
+                    assert isinstance(m_dn, DN)
                     if not m_dn:
                         continue
                     try:
@@ -1534,7 +1566,9 @@ class LDAPAddMember(LDAPModMember):
             (completed, dn) = callback(
                 self, ldap, completed, failed, dn, entry_attrs, *keys,
                 **options)
+            assert isinstance(dn, DN)
 
+        assert isinstance(dn, DN)
         entry_attrs['dn'] = dn
         self.obj.convert_attribute_members(entry_attrs, *keys, **options)
         return dict(
@@ -1544,9 +1578,11 @@ class LDAPAddMember(LDAPModMember):
         )
 
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         return dn
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return (completed, dn)
 
     def exc_callback(self, keys, options, exc, call_func, *call_args, **call_kwargs):
@@ -1583,14 +1619,17 @@ class LDAPRemoveMember(LDAPModMember):
         (member_dns, failed) = self.get_member_dns(**options)
 
         dn = self.obj.get_dn(*keys, **options)
+        assert isinstance(dn, DN)
 
         for callback in self.get_callbacks('pre'):
             dn = callback(self, ldap, dn, member_dns, failed, *keys, **options)
+            assert isinstance(dn, DN)
 
         completed = 0
         for (attr, objs) in member_dns.iteritems():
             for ldap_obj_name, m_dns in objs.iteritems():
                 for m_dn in m_dns:
+                    assert isinstance(m_dn, DN)
                     if not m_dn:
                         continue
                     try:
@@ -1625,7 +1664,9 @@ class LDAPRemoveMember(LDAPModMember):
             (completed, dn) = callback(
                 self, ldap, completed, failed, dn, entry_attrs, *keys,
                 **options)
+            assert isinstance(dn, DN)
 
+        assert isinstance(dn, DN)
         entry_attrs['dn'] = dn
 
         self.obj.convert_attribute_members(entry_attrs, *keys, **options)
@@ -1636,9 +1677,11 @@ class LDAPRemoveMember(LDAPModMember):
         )
 
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         return dn
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return (completed, dn)
 
     def exc_callback(self, keys, options, exc, call_func, *call_args, **call_kwargs):
@@ -1765,6 +1808,7 @@ class LDAPSearch(BaseLDAPCommand, crud.Search):
             base_dn = self.api.Object[self.obj.parent_object].get_dn(*args[:-1])
         else:
             base_dn = self.obj.container_dn
+        assert isinstance(base_dn, DN)
 
         search_kw = self.args_options_2_entry(**options)
 
@@ -1812,6 +1856,7 @@ class LDAPSearch(BaseLDAPCommand, crud.Search):
         for callback in self.get_callbacks('pre'):
             (filter, base_dn, scope) = callback(
                 self, ldap, filter, attrs_list, base_dn, scope, *args, **options)
+            assert isinstance(base_dn, DN)
 
         try:
             (entries, truncated) = self._exc_wrapper(args, options, ldap.find_entries)(
@@ -1827,14 +1872,16 @@ class LDAPSearch(BaseLDAPCommand, crud.Search):
 
         if self.sort_result_entries:
             if self.obj.primary_key:
-                sortfn=lambda x,y: cmp(x[1][self.obj.primary_key.name][0].lower(), y[1][self.obj.primary_key.name][0].lower())
-                entries.sort(sortfn)
+                def sort_key(x):
+                    return x[1][self.obj.primary_key.name][0].lower()
+                entries.sort(key=sort_key)
 
         if not options.get('raw', False):
             for e in entries:
                 self.obj.convert_attribute_members(e[1], *args, **options)
 
         for e in entries:
+            assert isinstance(e[0], DN)
             e[1]['dn'] = e[0]
         entries = [e for (dn, e) in entries]
 
@@ -1845,6 +1892,7 @@ class LDAPSearch(BaseLDAPCommand, crud.Search):
         )
 
     def pre_callback(self, ldap, filters, attrs_list, base_dn, scope, *args, **options):
+        assert isinstance(base_dn, DN)
         return (filters, base_dn, scope)
 
     def post_callback(self, ldap, entries, truncated, *args, **options):
@@ -1926,9 +1974,11 @@ class LDAPAddReverseMember(LDAPModReverseMember):
         # Ensure our target exists
         result = self.api.Command[self.show_command](keys[-1])['result']
         dn = result['dn']
+        assert isinstance(dn, DN)
 
         for callback in self.get_callbacks('pre'):
             dn = callback(self, ldap, dn, *keys, **options)
+            assert isinstance(dn, DN)
 
         if options.get('all', False):
             attrs_list = ['*'] + self.obj.default_attributes
@@ -1967,7 +2017,9 @@ class LDAPAddReverseMember(LDAPModReverseMember):
             (completed, dn) = callback(
                 self, ldap, completed, failed, dn, entry_attrs, *keys,
                 **options)
+            assert isinstance(dn, DN)
 
+        assert isinstance(dn, DN)
         entry_attrs['dn'] = dn
         return dict(
             completed=completed,
@@ -1976,9 +2028,11 @@ class LDAPAddReverseMember(LDAPModReverseMember):
         )
 
     def pre_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         return dn
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return (completed, dn)
 
     def exc_callback(self, keys, options, exc, call_func, *call_args, **call_kwargs):
@@ -2022,9 +2076,11 @@ class LDAPRemoveReverseMember(LDAPModReverseMember):
         # Ensure our target exists
         result = self.api.Command[self.show_command](keys[-1])['result']
         dn = result['dn']
+        assert isinstance(dn, DN)
 
         for callback in self.get_callbacks('pre'):
             dn = callback(self, ldap, dn, *keys, **options)
+            assert isinstance(dn, DN)
 
         if options.get('all', False):
             attrs_list = ['*'] + self.obj.default_attributes
@@ -2063,7 +2119,9 @@ class LDAPRemoveReverseMember(LDAPModReverseMember):
             (completed, dn) = callback(
                 self, ldap, completed, failed, dn, entry_attrs, *keys,
                 **options)
+            assert isinstance(dn, DN)
 
+        assert isinstance(dn, DN)
         entry_attrs['dn'] = dn
         return dict(
             completed=completed,
@@ -2072,9 +2130,11 @@ class LDAPRemoveReverseMember(LDAPModReverseMember):
         )
 
     def pre_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         return dn
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return (completed, dn)
 
     def exc_callback(self, keys, options, exc, call_func, *call_args, **call_kwargs):
diff --git a/ipalib/plugins/config.py b/ipalib/plugins/config.py
index 9573bbb65..ef0fd79fa 100644
--- a/ipalib/plugins/config.py
+++ b/ipalib/plugins/config.py
@@ -19,7 +19,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 from ipalib import api
-from ipalib import Bool, Int, Str, IA5Str, StrEnum
+from ipalib import Bool, Int, Str, IA5Str, StrEnum, DNParam
 from ipalib.plugins.baseldap import *
 from ipalib import _
 from ipalib.errors import ValidationError
@@ -149,7 +149,7 @@ class config(LDAPObject):
             label=_('Enable migration mode'),
             doc=_('Enable migration mode'),
         ),
-        Str('ipacertificatesubjectbase',
+        DNParam('ipacertificatesubjectbase',
             cli_name='subject',
             label=_('Certificate Subject base'),
             doc=_('Base for certificate subjects (OU=Test,O=Example)'),
@@ -199,7 +199,7 @@ class config(LDAPObject):
     )
 
     def get_dn(self, *keys, **kwargs):
-        return 'cn=ipaconfig,cn=etc'
+        return DN(('cn', 'ipaconfig'), ('cn', 'etc'))
 
 api.register(config)
 
@@ -208,6 +208,7 @@ class config_mod(LDAPUpdate):
     __doc__ = _('Modify configuration options.')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         if 'ipadefaultprimarygroup' in entry_attrs:
             group=entry_attrs['ipadefaultprimarygroup']
             try:
diff --git a/ipalib/plugins/dns.py b/ipalib/plugins/dns.py
index 6727d052f..991eb0164 100644
--- a/ipalib/plugins/dns.py
+++ b/ipalib/plugins/dns.py
@@ -35,7 +35,6 @@ from ipalib.util import (validate_zonemgr, normalize_zonemgr,
         validate_hostname, validate_dns_label, validate_domain_name,
         get_dns_forward_zone_update_policy, get_dns_reverse_zone_update_policy)
 from ipapython.ipautil import valid_ip, CheckedIPAddress, is_host_resolvable
-from ldap import explode_dn
 
 __doc__ = _("""
 Domain Name System (DNS)
@@ -802,10 +801,10 @@ class DNSRecord(Str):
 
     # callbacks for per-type special record behavior
     def dnsrecord_add_pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
-        pass
+        assert isinstance(dn, DN)
 
     def dnsrecord_add_post_callback(self, ldap, dn, entry_attrs, *keys, **options):
-        pass
+        assert isinstance(dn, DN)
 
 class ForwardRecord(DNSRecord):
     extra = (
@@ -817,6 +816,7 @@ class ForwardRecord(DNSRecord):
     )
 
     def dnsrecord_add_pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         reverse_option = self._convert_dnsrecord_extra(self.extra[0])
         if options.get(reverse_option.name):
             records = entry_attrs.get(self.name, [])
@@ -832,6 +832,7 @@ class ForwardRecord(DNSRecord):
             setattr(context, '%s_reverse' % self.name, entry_attrs.get(self.name))
 
     def dnsrecord_add_post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         rev_records = getattr(context, '%s_reverse' % self.name, [])
 
         if rev_records:
@@ -1727,6 +1728,7 @@ class dnszone_add(LDAPCreate):
     )
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         if not dns_container_exists(self.api.Backend.ldap2):
             raise errors.NotFound(reason=_('DNS is not configured'))
 
@@ -1751,6 +1753,7 @@ class dnszone_add(LDAPCreate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         if 'ip_address' in options:
             nameserver = entry_attrs['idnssoamname'][0][:-1] # ends with a dot
             nsparts = nameserver.split('.')
@@ -1813,6 +1816,7 @@ class dnszone_find(LDAPSearch):
     )
 
     def pre_callback(self, ldap, filter, attrs_list, base_dn, scope, *args, **options):
+        assert isinstance(base_dn, DN)
         if options.get('forward_only', False):
             search_kw = {}
             search_kw['idnsname'] = _valid_reverse_zones.keys()
@@ -1980,6 +1984,7 @@ class dnsrecord(LDAPObject):
                            )
 
     def _nsrecord_pre_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         nsrecords = entry_attrs.get('nsrecord')
         if options.get('force', False) or nsrecords is None:
             return
@@ -1987,6 +1992,7 @@ class dnsrecord(LDAPObject):
             check_ns_rec_resolvable(keys[0], nsrecord)
 
     def _ptrrecord_pre_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         ptrrecords = entry_attrs.get('ptrrecord')
         if ptrrecords is None:
             return
@@ -2015,6 +2021,7 @@ class dnsrecord(LDAPObject):
                 % dict(name=zone_name, count=zone_len, user_count=ip_addr_comp_count)))
 
     def run_precallback_validators(self, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         ldap = self.api.Backend.ldap2
 
         for rtype in entry_attrs:
@@ -2049,7 +2056,7 @@ class dnsrecord(LDAPObject):
 
     def get_dns_masters(self):
         ldap = self.api.Backend.ldap2
-        base_dn = 'cn=masters,cn=ipa,cn=etc,%s' % self.api.env.basedn
+        base_dn = DN(('cn', 'masters'), ('cn', 'ipa'), ('cn', 'etc'), self.api.env.basedn)
         ldap_filter = '(&(objectClass=ipaConfigObject)(cn=DNS))'
         dns_masters = []
 
@@ -2058,9 +2065,12 @@ class dnsrecord(LDAPObject):
 
             for entry in entries:
                 master_dn = entry[0]
-                if master_dn.startswith('cn='):
-                    master = explode_dn(master_dn)[1].replace('cn=','')
+                assert isinstance(master_dn, DN)
+                try:
+                    master = master_dn[1]['cn']
                     dns_masters.append(master)
+                except (IndexError, KeyError):
+                    pass
         except errors.NotFound:
             return []
 
@@ -2254,6 +2264,7 @@ class dnsrecord_add(LDAPCreate):
         kw.update(user_options)
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         precallback_attrs = []
         processed_attrs = []
         for option in options:
@@ -2354,6 +2365,7 @@ class dnsrecord_add(LDAPCreate):
         raise exc
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         for attr in getattr(context, 'dnsrecord_precallback_attrs', []):
             param = self.params[attr]
             param.dnsrecord_add_post_callback(ldap, dn, entry_attrs, *keys, **options)
@@ -2382,6 +2394,7 @@ class dnsrecord_mod(LDAPUpdate):
         return super(dnsrecord_mod, self).args_options_2_entry(*keys, **options)
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list,  *keys, **options):
+        assert isinstance(dn, DN)
         if options.get('rename') and self.obj.is_pkey_zone_record(*keys):
             # zone rename is not allowed
             raise errors.ValidationError(name='rename',
@@ -2466,10 +2479,12 @@ class dnsrecord_mod(LDAPUpdate):
         return result
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         if self.obj.is_pkey_zone_record(*keys):
             entry_attrs[self.obj.primary_key.name] = [_dns_zone_record]
 
         self.obj.postprocess_record(entry_attrs, **options)
+        return dn
 
     def interactive_prompt_callback(self, kw):
         try:
@@ -2564,6 +2579,7 @@ class dnsrecord_del(LDAPUpdate):
             yield option
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (dn_, old_entry) = ldap.get_entry(
                     dn, _record_attributes,
@@ -2626,9 +2642,11 @@ class dnsrecord_del(LDAPUpdate):
         return result
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         if self.obj.is_pkey_zone_record(*keys):
             entry_attrs[self.obj.primary_key.name] = [_dns_zone_record]
         self.obj.postprocess_record(entry_attrs, **options)
+        return dn
 
     def args_options_2_entry(self, *keys, **options):
         self.obj.has_cli_options(options, self.no_option_msg)
@@ -2697,6 +2715,7 @@ class dnsrecord_show(LDAPRetrieve):
     )
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         if self.obj.is_pkey_zone_record(*keys):
             entry_attrs[self.obj.primary_key.name] = [_dns_zone_record]
         self.obj.postprocess_record(entry_attrs, **options)
@@ -2723,6 +2742,7 @@ class dnsrecord_find(LDAPSearch):
             yield option
 
     def pre_callback(self, ldap, filter, attrs_list, base_dn, scope, *args, **options):
+        assert isinstance(base_dn, DN)
         # include zone record (root entry) in the search
         return (filter, base_dn, ldap.SCOPE_SUBTREE)
 
@@ -2774,7 +2794,7 @@ class dns_is_enabled(Command):
     NO_CLI = True
     has_output = output.standard_value
 
-    base_dn = 'cn=masters,cn=ipa,cn=etc,%s' % api.env.basedn
+    base_dn = DN(('cn', 'masters'), ('cn', 'ipa'), ('cn', 'etc'), api.env.basedn)
     filter = '(&(objectClass=ipaConfigObject)(cn=DNS))'
 
     def execute(self, *args, **options):
diff --git a/ipalib/plugins/entitle.py b/ipalib/plugins/entitle.py
index 5ccdb6510..67e7f959e 100644
--- a/ipalib/plugins/entitle.py
+++ b/ipalib/plugins/entitle.py
@@ -318,6 +318,7 @@ class entitle_consume(LDAPUpdate):
         return result
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         quantity = keys[-1]
 
         os.environ['LANG'] = 'en_US'
@@ -361,6 +362,7 @@ class entitle_consume(LDAPUpdate):
         Returning the certificates isn't very interesting. Return the
         status of entitlements instead.
         """
+        assert isinstance(dn, DN)
         if 'usercertificate' in entry_attrs:
             del entry_attrs['usercertificate']
         if 'userpkcs12' in entry_attrs:
@@ -504,7 +506,7 @@ class entitle_register(LDAPCreate):
     """
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
-        dn = '%s,%s' % (self.obj.container_dn, self.api.env.basedn)
+        dn = DN(self.obj.container_dn, self.api.env.basedn)
         if not ldap.can_add(dn):
             raise errors.ACIError(info='No permission to register')
         os.environ['LANG'] = 'en_US'
@@ -604,6 +606,7 @@ class entitle_import(LDAPUpdate):
     )
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (db, uuid, certfile, keyfile) = get_uuid(ldap)
             if db is not None:
@@ -622,7 +625,7 @@ class entitle_import(LDAPUpdate):
                     raise errors.CertificateFormatError(error=_('Not an entitlement certificate'))
             except M2Crypto.X509.X509Error:
                 raise errors.CertificateFormatError(error=_('Not an entitlement certificate'))
-            dn = 'ipaentitlementid=%s,%s' % (entry_attrs['ipaentitlementid'], dn)
+            dn = DN(('ipaentitlementid', entry_attrs['ipaentitlementid']), dn)
             (dn, current_attrs) = ldap.get_entry(
                 dn, ['*'], normalize=self.obj.normalize_dn
             )
@@ -689,6 +692,7 @@ class entitle_sync(LDAPUpdate):
     )
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         os.environ['LANG'] = 'en_US'
         locale.setlocale(locale.LC_ALL, '')
 
@@ -719,6 +723,7 @@ class entitle_sync(LDAPUpdate):
         Returning the certificates isn't very interesting. Return the
         status of entitlements instead.
         """
+        assert isinstance(dn, DN)
         if 'usercertificate' in entry_attrs:
             del entry_attrs['usercertificate']
         if 'userpkcs12' in entry_attrs:
diff --git a/ipalib/plugins/group.py b/ipalib/plugins/group.py
index 74bea1700..011587206 100644
--- a/ipalib/plugins/group.py
+++ b/ipalib/plugins/group.py
@@ -156,6 +156,7 @@ class group_add(LDAPCreate):
         # As both 'external' and 'nonposix' options have default= set for
         # them, they will always be present in options dict, thus we can
         # safely reference the values
+        assert isinstance(dn, DN)
         if options['external']:
             entry_attrs['objectclass'].append('ipaexternalgroup')
             if 'gidnumber' in options:
@@ -176,6 +177,7 @@ class group_del(LDAPDelete):
     msg_summary = _('Deleted group "%(value)s"')
 
     def pre_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         config = ldap.get_ipa_config()[1]
         def_primary_group = config.get('ipadefaultprimarygroup', '')
         def_primary_group_dn = group_dn = self.obj.get_dn(def_primary_group)
@@ -192,6 +194,7 @@ class group_del(LDAPDelete):
         return dn
 
     def post_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             api.Command['pwpolicy_del'](keys[-1])
         except errors.NotFound:
@@ -220,6 +223,7 @@ class group_mod(LDAPUpdate):
     )
 
     def pre_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         if ('posix' in options and options['posix']) or 'gidnumber' in options:
             (dn, old_entry_attrs) = ldap.get_entry(dn, ['objectclass'])
             if 'ipaexternalgroup' in old_entry_attrs['objectclass']:
@@ -275,6 +279,7 @@ class group_find(LDAPSearch):
     )
 
     def pre_callback(self, ldap, filter, attrs_list, base_dn, scope, *args, **options):
+        assert isinstance(base_dn, DN)
         # if looking for private groups, we need to create a new search filter,
         # because private groups have different object classes
         if options['private']:
@@ -319,6 +324,7 @@ class group_add_member(LDAPAddMember):
     )
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         result = (completed, dn)
         if 'ipaexternalmember' in options:
             if not _dcerpc_bindings_installed:
@@ -367,6 +373,7 @@ class group_remove_member(LDAPRemoveMember):
     )
 
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         if keys[0] == protected_group_name:
             result = api.Command.group_show(protected_group_name)
             users_left = set(result['result'].get('member_user', []))
@@ -377,6 +384,7 @@ class group_remove_member(LDAPRemoveMember):
         return dn
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         result = (completed, dn)
         if 'ipaexternalmember' in options:
             sids = options['ipaexternalmember']
diff --git a/ipalib/plugins/hbacrule.py b/ipalib/plugins/hbacrule.py
index 460083622..94f0d0e20 100644
--- a/ipalib/plugins/hbacrule.py
+++ b/ipalib/plugins/hbacrule.py
@@ -231,6 +231,7 @@ class hbacrule_add(LDAPCreate):
     msg_summary = _('Added HBAC rule "%(value)s"')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         # HBAC rules are enabled by default
         entry_attrs['ipaenabledflag'] = 'TRUE'
         return dn
@@ -244,6 +245,7 @@ class hbacrule_del(LDAPDelete):
     msg_summary = _('Deleted HBAC rule "%(value)s"')
 
     def pre_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         kw = dict(seealso=keys[0])
         _entries = api.Command.selinuxusermap_find(None, **kw)
         if _entries['count']:
@@ -260,6 +262,7 @@ class hbacrule_mod(LDAPUpdate):
     msg_summary = _('Modified HBAC rule "%(value)s"')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (dn, entry_attrs) = ldap.get_entry(dn, attrs_list)
         except errors.NotFound:
@@ -436,6 +439,7 @@ class hbacrule_add_user(LDAPAddMember):
     member_count_out = ('%i object added.', '%i objects added.')
 
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (dn, entry_attrs) = ldap.get_entry(dn, self.obj.default_attributes)
         except errors.NotFound:
@@ -464,6 +468,7 @@ class hbacrule_add_host(LDAPAddMember):
     member_count_out = ('%i object added.', '%i objects added.')
 
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (dn, entry_attrs) = ldap.get_entry(dn, self.obj.default_attributes)
         except errors.NotFound:
@@ -492,6 +497,7 @@ class hbacrule_add_sourcehost(LDAPAddMember):
     member_count_out = ('%i object added.', '%i objects added.')
 
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (dn, entry_attrs) = ldap.get_entry(dn, self.obj.default_attributes)
         except errors.NotFound:
@@ -502,6 +508,7 @@ class hbacrule_add_sourcehost(LDAPAddMember):
         return add_external_pre_callback('host', ldap, dn, keys, options)
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return add_external_post_callback('sourcehost', 'host', 'externalhost', ldap, completed, failed, dn, entry_attrs, keys, options)
 
 api.register(hbacrule_add_sourcehost)
@@ -514,6 +521,7 @@ class hbacrule_remove_sourcehost(LDAPRemoveMember):
     member_count_out = ('%i object removed.', '%i objects removed.')
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return remove_external_post_callback('sourcehost', 'host', 'externalhost', ldap, completed, failed, dn, entry_attrs, keys, options)
 
 api.register(hbacrule_remove_sourcehost)
@@ -526,6 +534,7 @@ class hbacrule_add_service(LDAPAddMember):
     member_count_out = ('%i object added.', '%i objects added.')
 
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (dn, entry_attrs) = ldap.get_entry(dn, self.obj.default_attributes)
         except errors.NotFound:
diff --git a/ipalib/plugins/host.py b/ipalib/plugins/host.py
index e8967b8c0..a417ba0f7 100644
--- a/ipalib/plugins/host.py
+++ b/ipalib/plugins/host.py
@@ -38,10 +38,10 @@ from ipalib.plugins.dns import (dns_container_exists, _record_types,
 from ipalib.plugins.dns import get_reverse_zone
 from ipalib import _, ngettext
 from ipalib import x509
-from ipalib.dn import *
 from ipalib.request import context
 from ipalib.util import validate_sshpubkey, output_sshpubkey
 from ipapython.ipautil import ipa_generate_password, CheckedIPAddress, make_sshfp
+from ipapython.dn import DN
 
 __doc__ = _("""
 Hosts/Machines
@@ -379,6 +379,7 @@ class host_add(LDAPCreate):
     )
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         if options.get('ip_address') and dns_container_exists(ldap):
             parts = keys[-1].split('.')
             host = parts[0]
@@ -423,6 +424,7 @@ class host_add(LDAPCreate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         exc = None
         if dns_container_exists(ldap):
             try:
@@ -483,6 +485,7 @@ class host_del(LDAPDelete):
     )
 
     def pre_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         # If we aren't given a fqdn, find it
         if _hostname_validator(None, keys[-1]) is not None:
             hostentry = api.Command['host_show'](keys[-1])['result']
@@ -599,6 +602,7 @@ class host_mod(LDAPUpdate):
     )
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         # Allow an existing OTP to be reset but don't allow a OTP to be
         # added to an enrolled host.
         if options.get('userpassword') or options.get('random'):
@@ -690,6 +694,7 @@ class host_mod(LDAPUpdate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         if options.get('random', False):
             entry_attrs['randompassword'] = unicode(getattr(context, 'randompassword'))
         set_certificate_attrs(entry_attrs)
@@ -728,6 +733,7 @@ class host_find(LDAPSearch):
             yield option
 
     def pre_callback(self, ldap, filter, attrs_list, base_dn, scope, *args, **options):
+        assert isinstance(base_dn, DN)
         if 'locality' in attrs_list:
             attrs_list.remove('locality')
             attrs_list.append('l')
@@ -808,6 +814,7 @@ class host_show(LDAPRetrieve):
     member_attributes = ['managedby']
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.get_password_attributes(ldap, dn, entry_attrs)
         if entry_attrs['has_password']:
             # If an OTP is set there is no keytab, at least not one
@@ -891,8 +898,7 @@ class host_disable(LDAPQuery):
             try:
                 serial = unicode(x509.get_serial_number(cert, x509.DER))
                 try:
-                    result = api.Command['cert_show'](unicode(serial))['result'
-]
+                    result = api.Command['cert_show'](unicode(serial))['result']
                     if 'revocation_reason' not in result:
                         try:
                             api.Command['cert_revoke'](unicode(serial), revocation_reason=4)
@@ -928,6 +934,7 @@ class host_disable(LDAPQuery):
         )
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.suppress_netgroup_memberof(entry_attrs)
         return dn
 
@@ -941,6 +948,7 @@ class host_add_managedby(LDAPAddMember):
     allow_same = True
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.suppress_netgroup_memberof(entry_attrs)
         return (completed, dn)
 
@@ -954,6 +962,7 @@ class host_remove_managedby(LDAPRemoveMember):
     has_output_params = LDAPRemoveMember.has_output_params + host_output_params
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.suppress_netgroup_memberof(entry_attrs)
         return (completed, dn)
 
diff --git a/ipalib/plugins/hostgroup.py b/ipalib/plugins/hostgroup.py
index b68c45842..7e6fe6d65 100644
--- a/ipalib/plugins/hostgroup.py
+++ b/ipalib/plugins/hostgroup.py
@@ -21,7 +21,7 @@
 from ipalib.plugins.baseldap import *
 from ipalib import api, Int, _, ngettext, errors
 from ipalib.plugins.netgroup import NETGROUP_PATTERN, NETGROUP_PATTERN_ERRMSG
-from ipalib.dn import DN
+from ipapython.dn import DN
 
 __doc__ = _("""
 Groups of hosts.
@@ -119,6 +119,7 @@ class hostgroup_add(LDAPCreate):
     msg_summary = _('Added hostgroup "%(value)s"')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             # check duplicity with hostgroups first to provide proper error
             netgroup = api.Command['hostgroup_show'](keys[-1])
@@ -140,6 +141,7 @@ class hostgroup_add(LDAPCreate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         # Always wait for the associated netgroup to be created so we can
         # be sure to ignore it in memberOf
         newentry = wait_for_value(ldap, dn, 'objectclass', 'mepOriginEntry')
@@ -166,6 +168,7 @@ class hostgroup_mod(LDAPUpdate):
     msg_summary = _('Modified hostgroup "%(value)s"')
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.suppress_netgroup_memberof(dn, entry_attrs)
         return dn
 
@@ -195,6 +198,7 @@ class hostgroup_show(LDAPRetrieve):
     __doc__ = _('Display information about a hostgroup.')
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.suppress_netgroup_memberof( dn, entry_attrs)
         return dn
 
@@ -205,6 +209,7 @@ class hostgroup_add_member(LDAPAddMember):
     __doc__ = _('Add members to a hostgroup.')
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.suppress_netgroup_memberof(dn, entry_attrs)
         return (completed, dn)
 
@@ -215,6 +220,7 @@ class hostgroup_remove_member(LDAPRemoveMember):
     __doc__ = _('Remove members from a hostgroup.')
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.suppress_netgroup_memberof(dn, entry_attrs)
         return (completed, dn)
 
diff --git a/ipalib/plugins/krbtpolicy.py b/ipalib/plugins/krbtpolicy.py
index 0f80c770c..60674cc06 100644
--- a/ipalib/plugins/krbtpolicy.py
+++ b/ipalib/plugins/krbtpolicy.py
@@ -71,7 +71,7 @@ class krbtpolicy(LDAPObject):
     """
     Kerberos Ticket Policy object
     """
-    container_dn = 'cn=%s,cn=kerberos' % api.env.realm
+    container_dn = DN(('cn', api.env.realm), ('cn', 'kerberos'))
     object_name = _('kerberos ticket policy settings')
     default_attributes = ['krbmaxticketlife', 'krbmaxrenewableage']
     limit_object_classes = ['krbticketpolicyaux']
@@ -112,6 +112,7 @@ class krbtpolicy_mod(LDAPUpdate):
     __doc__ = _('Modify Kerberos ticket policy.')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         # disable all flag
         #  ticket policies are attached to objects with unrelated attributes
         if options.get('all'):
@@ -125,6 +126,7 @@ class krbtpolicy_show(LDAPRetrieve):
     __doc__ = _('Display the current Kerberos ticket policy.')
 
     def pre_callback(self, ldap, dn, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         # disable all flag
         #  ticket policies are attached to objects with unrelated attributes
         if options.get('all'):
@@ -132,6 +134,7 @@ class krbtpolicy_show(LDAPRetrieve):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         if keys[-1] is not None:
             # if policy for a specific user isn't set, display global values
             if 'krbmaxticketlife' not in entry_attrs or \
diff --git a/ipalib/plugins/migration.py b/ipalib/plugins/migration.py
index a8c1c6d82..157ab4447 100644
--- a/ipalib/plugins/migration.py
+++ b/ipalib/plugins/migration.py
@@ -21,10 +21,8 @@ import re
 import ldap as _ldap
 
 from ipalib import api, errors, output
-from ipalib import Command, Password, Str, Flag, StrEnum
+from ipalib import Command, Password, Str, Flag, StrEnum, DNParam
 from ipalib.cli import to_cli
-from ipalib.util import validate_dn_param
-from ipalib.dn import *
 from ipalib.plugins.user import NO_UPG_MAGIC
 if api.env.in_server and api.env.context in ['lite', 'server']:
     try:
@@ -32,6 +30,7 @@ if api.env.in_server and api.env.context in ['lite', 'server']:
     except StandardError, e:
         raise e
 from ipalib import _
+from ipapython.dn import DN
 
 __doc__ = _("""
 Migration to IPA
@@ -114,18 +113,10 @@ _dn_err_msg = _('Malformed DN')
 
 _supported_schemas = (u'RFC2307bis', u'RFC2307')
 
-_compat_dn = "cn=Schema Compatibility,cn=plugins,cn=config"
-
-def is_DN_syntax(ldap, attr):
-    """
-    Check the schema to see if the attribute uses DN syntax.
-
-    Returns True/False
-    """
-    obj = ldap.schema.get_obj(_ldap.schema.AttributeType, attr)
-    return obj is not None and obj.syntax == '1.3.6.1.4.1.1466.115.121.1.12'
+_compat_dn = DN(('cn', 'Schema Compatibility'), ('cn', 'plugins'), ('cn', 'config'))
 
 def _pre_migrate_user(ldap, pkey, dn, entry_attrs, failed, config, ctx, **kwargs):
+    assert isinstance(dn, DN)
     attr_blacklist = ['krbprincipalkey','memberofindirect','memberindirect']
     attr_blacklist.extend(kwargs.get('attr_blacklist', []))
     ds_ldap = ctx['ds_ldap']
@@ -198,17 +189,18 @@ def _pre_migrate_user(ldap, pkey, dn, entry_attrs, failed, config, ctx, **kwargs
     # tree
 
     for attr in entry_attrs.keys():
-        if is_DN_syntax(ldap, attr):
+        if ldap.has_dn_syntax(attr):
             for ind, value in enumerate(entry_attrs[attr]):
+                assert isinstance(value, DN)
                 try:
                     (remote_dn, remote_entry) = ds_ldap.get_entry(value, [api.Object.user.primary_key.name, api.Object.group.primary_key.name])
                 except errors.NotFound:
                     api.log.warn('%s: attribute %s refers to non-existent entry %s' % (pkey, attr, value))
                     continue
-                if value.lower().endswith(search_bases['user']):
+                if value.endswith(search_bases['user']):
                     primary_key = api.Object.user.primary_key.name
                     container = api.env.container_user
-                elif value.lower().endswith(search_bases['group']):
+                elif value.endswith(search_bases['group']):
                     primary_key = api.Object.group.primary_key.name
                     container = api.env.container_group
                 else:
@@ -221,15 +213,13 @@ def _pre_migrate_user(ldap, pkey, dn, entry_attrs, failed, config, ctx, **kwargs
 
                 api.log.debug('converting DN value %s for %s in %s' % (value, attr, dn))
                 rdnval = remote_entry[primary_key][0].lower()
-                entry_attrs[attr][ind] = \
-                    str(DN((primary_key, rdnval),
-                    container,
-                    api.env.basedn))
+                entry_attrs[attr][ind] = DN((primary_key, rdnval), container, api.env.basedn)
 
     return dn
 
 
 def _post_migrate_user(ldap, pkey, dn, entry_attrs, failed, config, ctx):
+    assert isinstance(dn, DN)
     # add user to the default group
     try:
         ldap.add_entry_to_group(dn, ctx['def_group_dn'])
@@ -246,6 +236,7 @@ def _post_migrate_user(ldap, pkey, dn, entry_attrs, failed, config, ctx):
 # GROUP MIGRATION CALLBACKS AND VARS
 
 def _pre_migrate_group(ldap, pkey, dn, entry_attrs, failed, config, ctx, **kwargs):
+
     def convert_members_rfc2307bis(member_attr, search_bases, overwrite=False):
         """
         Convert DNs in member attributes to work in IPA.
@@ -253,24 +244,19 @@ def _pre_migrate_group(ldap, pkey, dn, entry_attrs, failed, config, ctx, **kwarg
         new_members = []
         entry_attrs.setdefault(member_attr, [])
         for m in entry_attrs[member_attr]:
+            assert isinstance(m, DN)
             try:
-                # what str2dn returns looks like [[('cn', 'foo', 4)], [('dc', 'example', 1)], [('dc', 'com', 1)]]
-                rdn = _ldap.dn.str2dn(m ,flags=_ldap.DN_FORMAT_LDAPV3)[0]
-                rdnval = rdn[0][1]
+                rdnval = m[0].value
             except IndexError:
                 api.log.error('Malformed DN %s has no RDN?' % m)
                 continue
 
-            if m.lower().endswith(search_bases['user']):
+            if m.endswith(search_bases['user']):
                 api.log.info('migrating user %s' % m)
-                m = '%s=%s,%s' % (api.Object.user.primary_key.name,
-                                  rdnval,
-                                  api.env.container_user)
-            elif m.lower().endswith(search_bases['group']):
+                m = DN((api.Object.user.primary_key.name, rdnval), api.env.container_user)
+            elif m.endswith(search_bases['group']):
                 api.log.info('migrating group %s' % m)
-                m = '%s=%s,%s' % (api.Object.group.primary_key.name,
-                                  rdnval,
-                                  api.env.container_group)
+                m = DN((api.Object.group.primary_key.name, rdnval), api.env.container_group)
             else:
                 api.log.error('entry %s does not belong into any known container' % m)
                 continue
@@ -290,12 +276,11 @@ def _pre_migrate_group(ldap, pkey, dn, entry_attrs, failed, config, ctx, **kwarg
         new_members = []
         entry_attrs.setdefault(member_attr, [])
         for m in entry_attrs[member_attr]:
-            memberdn = '%s=%s,%s' % (api.Object.user.primary_key.name,
-                                     m,
-                                     api.env.container_user)
+            memberdn = DN((api.Object.user.primary_key.name, m), api.env.container_user)
             new_members.append(ldap.normalize_dn(memberdn))
         entry_attrs['member'] = new_members
 
+    assert isinstance(dn, DN)
     attr_blacklist = ['memberofindirect','memberindirect']
     attr_blacklist.extend(kwargs.get('attr_blacklist', []))
 
@@ -330,6 +315,7 @@ def _pre_migrate_group(ldap, pkey, dn, entry_attrs, failed, config, ctx, **kwarg
 
 
 def _group_exc_callback(ldap, dn, entry_attrs, exc, options):
+    assert isinstance(dn, DN)
     if isinstance(exc, errors.DuplicateEntry):
         if options.get('groupoverwritegid', False) and \
            entry_attrs.get('gidnumber') is not None:
@@ -424,24 +410,24 @@ class migrate_ds(Command):
     )
 
     takes_options = (
-        Str('binddn?', validate_dn_param,
+        DNParam('binddn?',
             cli_name='bind_dn',
             label=_('Bind DN'),
-            default=u'cn=directory manager',
+            default=DN(('cn', 'directory manager')),
             autofill=True,
         ),
-        Str('usercontainer', validate_dn_param,
+        DNParam('usercontainer',
             cli_name='user_container',
             label=_('User container'),
             doc=_('DN of container for users in DS relative to base DN'),
-            default=u'ou=people',
+            default=DN(('ou', 'people')),
             autofill=True,
         ),
-        Str('groupcontainer', validate_dn_param,
+        DNParam('groupcontainer',
             cli_name='group_container',
             label=_('Group container'),
             doc=_('DN of container for groups in DS relative to base DN'),
-            default=u'ou=groups',
+            default=DN(('ou', 'groups')),
             autofill=True,
         ),
         Str('userobjectclass+',
@@ -511,7 +497,7 @@ class migrate_ds(Command):
             doc=_('Continuous operation mode. Errors are reported but the process continues'),
             default=False,
         ),
-        Str('basedn?',
+        DNParam('basedn?',
             cli_name='base_dn',
             label=_('Base DN'),
             doc=_('Base DN on remote LDAP server'),
@@ -594,11 +580,9 @@ can use their Kerberos accounts.''')
 
     def _get_search_bases(self, options, ds_base_dn, migrate_order):
         search_bases = dict()
-        ds_base_dn = DN(ds_base_dn)
         for ldap_obj_name in migrate_order:
             container = options.get('%scontainer' % to_cli(ldap_obj_name))
             if container:
-                container = DN(container)
                 # Don't append base dn if user already appended it in the container dn
                 if container.endswith(ds_base_dn):
                     search_base = container
@@ -606,13 +590,14 @@ can use their Kerberos accounts.''')
                     search_base = DN(container, ds_base_dn)
             else:
                 search_base = ds_base_dn
-            search_bases[ldap_obj_name] = str(search_base)
+            search_bases[ldap_obj_name] = search_base
         return search_bases
 
     def migrate(self, ldap, config, ds_ldap, ds_base_dn, options):
         """
         Migrate objects from DS to LDAP.
         """
+        assert isinstance(ds_base_dn, DN)
         migrated = {} # {'OBJ': ['PKEY1', 'PKEY2', ...], ...}
         failed = {} # {'OBJ': {'PKEY1': 'Failed 'cos blabla', ...}, ...}
         search_bases = self._get_search_bases(options, ds_base_dn, self.migrate_order)
@@ -703,6 +688,7 @@ can use their Kerberos accounts.''')
                     continue
 
                 dn = ldap_obj.get_dn(pkey)
+                assert isinstance(dn, DN)
                 entry_attrs['objectclass'] = list(
                     set(
                         config.get(
@@ -722,6 +708,7 @@ can use their Kerberos accounts.''')
                             valid_gids = valid_gids,
                             **blacklists
                         )
+                        assert isinstance(dn, DN)
                         if not dn:
                             continue
                     except errors.NotFound, e:
@@ -760,6 +747,8 @@ can use their Kerberos accounts.''')
         config = ldap.get_ipa_config()[1]
 
         ds_base_dn = options.get('basedn')
+        if ds_base_dn is not None:
+            assert isinstance(ds_base_dn, DN)
 
         # check if migration mode is enabled
         if config.get('ipamigrationenabled', ('FALSE', ))[0] == 'FALSE':
@@ -773,6 +762,7 @@ can use their Kerberos accounts.''')
         if not options.get('compat'):
             try:
                 (dn,check_compat) = ldap.get_entry(_compat_dn, normalize=False)
+                assert isinstance(dn, DN)
                 if check_compat is not None and \
                         check_compat.get('nsslapd-pluginenabled', [''])[0].lower() == 'on':
                     return dict(result={}, failed={}, enabled=True, compat=False)
@@ -782,14 +772,16 @@ can use their Kerberos accounts.''')
         if not ds_base_dn:
             # retrieve base DN from remote LDAP server
             (entries, truncated) = ds_ldap.find_entries(
-                '', ['namingcontexts', 'defaultnamingcontext'], '',
+                '', ['namingcontexts', 'defaultnamingcontext'], DN(''),
                 _ldap.SCOPE_BASE, size_limit=-1, time_limit=0,
             )
             if 'defaultnamingcontext' in entries[0][1]:
-                ds_base_dn = entries[0][1]['defaultnamingcontext'][0]
+                ds_base_dn = DN(entries[0][1]['defaultnamingcontext'][0])
+                assert isinstance(ds_base_dn, DN)
             else:
                 try:
-                    ds_base_dn = entries[0][1]['namingcontexts'][0]
+                    ds_base_dn = DN(entries[0][1]['namingcontexts'][0])
+                    assert isinstance(ds_base_dn, DN)
                 except (IndexError, KeyError), e:
                     raise StandardError(str(e))
 
diff --git a/ipalib/plugins/netgroup.py b/ipalib/plugins/netgroup.py
index 4236feeb7..263d66b55 100644
--- a/ipalib/plugins/netgroup.py
+++ b/ipalib/plugins/netgroup.py
@@ -162,6 +162,7 @@ class netgroup_add(LDAPCreate):
                       u'Hostgroups and netgroups share a common namespace')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         entry_attrs.setdefault('nisdomainname', self.api.env.domain)
 
         try:
@@ -203,6 +204,7 @@ class netgroup_mod(LDAPUpdate):
     msg_summary = _('Modified netgroup "%(value)s"')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (dn, entry_attrs) = ldap.get_entry(dn, attrs_list)
         except errors.NotFound:
@@ -238,6 +240,7 @@ class netgroup_find(LDAPSearch):
     )
 
     def pre_callback(self, ldap, filter, attrs_list, base_dn, scope, *args, **options):
+        assert isinstance(base_dn, DN)
         # Do not display private mepManagedEntry netgroups by default
         # If looking for managed groups, we need to omit the negation search filter
 
@@ -267,8 +270,11 @@ class netgroup_add_member(LDAPAddMember):
     member_attributes = ['memberuser', 'memberhost', 'member']
     has_output_params = LDAPAddMember.has_output_params + output_params
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         return add_external_pre_callback('host', ldap, dn, keys, options)
+
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return add_external_post_callback('memberhost', 'host', 'externalhost', ldap, completed, failed, dn, entry_attrs, keys, options)
 
 api.register(netgroup_add_member)
@@ -280,6 +286,7 @@ class netgroup_remove_member(LDAPRemoveMember):
     member_attributes = ['memberuser', 'memberhost', 'member']
     has_output_params = LDAPRemoveMember.has_output_params + output_params
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return remove_external_post_callback('memberhost', 'host', 'externalhost', ldap, completed, failed, dn, entry_attrs, keys, options)
 
 api.register(netgroup_remove_member)
diff --git a/ipalib/plugins/passwd.py b/ipalib/plugins/passwd.py
index 9bee314ec..2c83560b1 100644
--- a/ipalib/plugins/passwd.py
+++ b/ipalib/plugins/passwd.py
@@ -24,6 +24,7 @@ from ipalib import _
 from ipalib import output
 from ipalib.plugins.user import split_principal, validate_principal, normalize_principal
 from ipalib.request import context
+from ipapython.dn import DN
 
 __doc__ = _("""
 Set a user's password
@@ -104,7 +105,7 @@ class passwd(Command):
 
         (dn, entry_attrs) = ldap.find_entry_by_attr(
             'krbprincipalname', principal, 'posixaccount', [''],
-            ",".join([api.env.container_user, api.env.basedn])
+            DN(api.env.container_user, api.env.basedn)
         )
 
         if principal == getattr(context, 'principal') and \
diff --git a/ipalib/plugins/permission.py b/ipalib/plugins/permission.py
index 89f9eaa62..befa74df8 100644
--- a/ipalib/plugins/permission.py
+++ b/ipalib/plugins/permission.py
@@ -22,6 +22,7 @@ from ipalib import api, _, ngettext
 from ipalib import Flag, Str, StrEnum
 from ipalib.request import context
 from ipalib import errors
+from ipapython.dn import DN, EditableDN
 
 __doc__ = _("""
 Permissions
@@ -202,6 +203,7 @@ class permission_add(LDAPCreate):
     has_output_params = LDAPCreate.has_output_params + output_params
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         # Test the ACI before going any further
         opts = self.obj.filter_aci_attributes(options)
         opts['test'] = True
@@ -219,6 +221,7 @@ class permission_add(LDAPCreate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         # Now actually add the aci.
         opts = self.obj.filter_aci_attributes(options)
         opts['test'] = False
@@ -275,6 +278,7 @@ class permission_add_noaci(LDAPCreate):
             yield option
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         permission_type = options.get('permissiontype')
         if permission_type:
             entry_attrs['ipapermissiontype'] = [ permission_type ]
@@ -297,6 +301,7 @@ class permission_del(LDAPDelete):
     )
 
     def pre_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         if not options.get('force') and not self.obj.check_system(ldap, dn, *keys):
             raise errors.ACIError(info='A SYSTEM permission may not be removed')
         # remove permission even when the underlying ACI is missing
@@ -316,6 +321,7 @@ class permission_mod(LDAPUpdate):
     has_output_params = LDAPUpdate.has_output_params + output_params
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         if not self.obj.check_system(ldap, dn, *keys):
             raise errors.ACIError(info='A SYSTEM permission may not be modified')
 
@@ -332,10 +338,13 @@ class permission_mod(LDAPUpdate):
         if 'rename' in options:
             if options['rename']:
                 try:
-                    new_dn = dn.replace(keys[-1].lower(), options['rename'], 1)
-                    (new_dn, attrs) = ldap.get_entry(
-                        new_dn, attrs_list, normalize=self.obj.normalize_dn
-                    )
+                    try:
+                        new_dn = EditableDN(dn)
+                        new_dn[0]['cn'] # assure the first RDN has cn as it's type
+                    except (IndexError, KeyError), e:
+                        raise ValueError("expected dn starting with 'cn=' but got '%s'" % dn)
+                    new_dn[0].value = options['rename']
+                    (new_dn, attrs) = ldap.get_entry(new_dn, attrs_list, normalize=self.obj.normalize_dn)
                     raise errors.DuplicateEntry()
                 except errors.NotFound:
                     pass    # permission may be renamed, continue
@@ -371,6 +380,7 @@ class permission_mod(LDAPUpdate):
         raise exc
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         # rename the underlying ACI after the change to permission
         cn = keys[-1]
 
@@ -480,6 +490,7 @@ class permission_show(LDAPRetrieve):
 
     has_output_params = LDAPRetrieve.has_output_params + output_params
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             common_options = filter_options(options, ['all', 'raw'])
             aci = self.api.Command.aci_show(keys[-1], aciprefix=ACI_PREFIX,
diff --git a/ipalib/plugins/pkinit.py b/ipalib/plugins/pkinit.py
index cb3b9c2fc..2d11f0244 100644
--- a/ipalib/plugins/pkinit.py
+++ b/ipalib/plugins/pkinit.py
@@ -21,6 +21,7 @@ from ipalib import api, errors
 from ipalib import Int, Str
 from ipalib import Object, Command
 from ipalib import _
+from ipapython.dn import DN
 
 __doc__ = _("""
 Kerberos pkinit options
@@ -67,9 +68,7 @@ class pkinit_anonymous(Command):
     __doc__ = _('Enable or Disable Anonymous PKINIT.')
 
     princ_name = 'WELLKNOWN/ANONYMOUS@%s' % api.env.realm
-    default_dn = 'krbprincipalname=%s,cn=%s,cn=kerberos,%s' % (
-        princ_name, api.env.realm, api.env.basedn
-    )
+    default_dn = DN(('krbprincipalname', princ_name), ('cn', api.env.realm), ('cn', 'kerberos'), api.env.basedn)
 
     takes_args = (
         Str('action', valid_arg),
diff --git a/ipalib/plugins/pwpolicy.py b/ipalib/plugins/pwpolicy.py
index 77e6f2c79..33c8329f7 100644
--- a/ipalib/plugins/pwpolicy.py
+++ b/ipalib/plugins/pwpolicy.py
@@ -19,11 +19,12 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 from ipalib import api
-from ipalib import Int, Str
+from ipalib import Int, Str, DNParam
 from ipalib.plugins.baseldap import *
 from ipalib import _
 from ipalib.request import context
 from ipapython.ipautil import run
+from ipapython.dn import DN
 from distutils import version
 
 __doc__ = _("""
@@ -75,13 +76,13 @@ class cosentry(LDAPObject):
     """
     NO_CLI = True
 
-    container_dn = 'cn=costemplates,%s' % api.env.container_accounts
+    container_dn = DN(('cn', 'costemplates'), api.env.container_accounts)
     object_class = ['top', 'costemplate', 'extensibleobject', 'krbcontainer']
     default_attributes = ['cn', 'cospriority', 'krbpwdpolicyreference']
 
     takes_params = (
         Str('cn', primary_key=True),
-        Str('krbpwdpolicyreference'),
+        DNParam('krbpwdpolicyreference'),
         Int('cospriority', minvalue=0),
     )
 
@@ -102,8 +103,7 @@ class cosentry(LDAPObject):
             )['result']
             if len(entries) > 0:
                 group_name = self.api.Object.group.get_primary_key_from_dn(
-                    entries[0]['cn'][0]
-                )
+                    DN(entries[0]['cn'][0]))
                 raise errors.ValidationError(
                     name='priority',
                     error=self.priority_not_unique_msg % {
@@ -119,6 +119,7 @@ class cosentry_add(LDAPCreate):
     NO_CLI = True
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         # check for existence of the group
         result = self.api.Command.group_show(keys[-1], all=True)['result']
         oc = map(lambda x:x.lower(),result['objectclass'])
@@ -141,6 +142,7 @@ class cosentry_mod(LDAPUpdate):
     NO_CLI = True
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         new_cospriority = options.get('cospriority')
         if new_cospriority is not None:
             cos_entry = self.api.Command.cosentry_show(keys[-1])['result']
@@ -167,13 +169,13 @@ api.register(cosentry_find)
 
 
 global_policy_name = 'global_policy'
-global_policy_dn = 'cn=%s,cn=%s,cn=kerberos,%s' % (global_policy_name, api.env.realm, api.env.basedn)
+global_policy_dn = DN(('cn', global_policy_name), ('cn', api.env.realm), ('cn', 'kerberos'), api.env.basedn)
 
 class pwpolicy(LDAPObject):
     """
     Password Policy object
     """
-    container_dn = 'cn=%s,cn=kerberos' % api.env.realm
+    container_dn = DN(('cn', api.env.realm), ('cn', 'kerberos'))
     object_name = _('password policy')
     object_name_plural = _('password policies')
     object_class = ['top', 'nscontainer', 'krbpwdpolicy']
@@ -339,6 +341,7 @@ class pwpolicy_add(LDAPCreate):
         yield self.obj.primary_key.clone(attribute=True, required=True)
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.convert_time_on_input(entry_attrs)
         self.obj.validate_lifetime(entry_attrs, True)
         self.api.Command.cosentry_add(
@@ -348,6 +351,7 @@ class pwpolicy_add(LDAPCreate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.log.info('%r' % entry_attrs)
         # attribute rights are not allowed for pwpolicy_add
         self.obj.add_cospriority(entry_attrs, keys[-1], rights=False)
@@ -366,7 +370,8 @@ class pwpolicy_del(LDAPDelete):
         )
 
     def pre_callback(self, ldap, dn, *keys, **options):
-        if dn.lower() == global_policy_dn.lower():
+        assert isinstance(dn, DN)
+        if dn == global_policy_dn:
             raise errors.ValidationError(
                 name='group',
                 error=_('cannot delete global password policy')
@@ -374,6 +379,7 @@ class pwpolicy_del(LDAPDelete):
         return dn
 
     def post_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             self.api.Command.cosentry_del(keys[-1])
         except errors.NotFound:
@@ -387,6 +393,7 @@ class pwpolicy_mod(LDAPUpdate):
     __doc__ = _('Modify a group password policy.')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.convert_time_on_input(entry_attrs)
         self.obj.validate_lifetime(entry_attrs, False, *keys)
         setattr(context, 'cosupdate', False)
@@ -408,6 +415,7 @@ class pwpolicy_mod(LDAPUpdate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         rights = options.get('all', False) and options.get('rights', False)
         self.obj.add_cospriority(entry_attrs, keys[-1], rights)
         self.obj.convert_time_for_output(entry_attrs, **options)
@@ -436,6 +444,7 @@ class pwpolicy_show(LDAPRetrieve):
     )
 
     def pre_callback(self, ldap, dn, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         if options.get('user') is not None:
             user_entry = self.api.Command.user_show(
                 options['user'], all=True
@@ -445,6 +454,7 @@ class pwpolicy_show(LDAPRetrieve):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         rights = options.get('all', False) and options.get('rights', False)
         self.obj.add_cospriority(entry_attrs, keys[-1], rights)
         self.obj.convert_time_for_output(entry_attrs, **options)
diff --git a/ipalib/plugins/range.py b/ipalib/plugins/range.py
index 39849b661..c1d918679 100644
--- a/ipalib/plugins/range.py
+++ b/ipalib/plugins/range.py
@@ -96,6 +96,7 @@ class range_add(LDAPCreate):
     msg_summary = _('Added ID range "%(value)s"')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         if ('ipanttrusteddomainsid' not in options and
             'ipasecondarybaserid' not in options):
             raise errors.ValidationError(name=_('Range setup'),
@@ -110,6 +111,7 @@ class range_add(LDAPCreate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.handle_iparangetype(entry_attrs, options, keep_objectclass=True)
         return dn
 
@@ -128,6 +130,7 @@ class range_find(LDAPSearch):
     # Since all range types are stored within separate containers under
     # 'cn=ranges,cn=etc' search can be done on a one-level scope
     def pre_callback(self, ldap, filters, attrs_list, base_dn, scope, *args, **options):
+        assert isinstance(base_dn, DN)
         attrs_list.append('objectclass')
         return (filters, base_dn, ldap.SCOPE_ONELEVEL)
 
@@ -140,10 +143,12 @@ class range_show(LDAPRetrieve):
     __doc__ = _('Display information about a range.')
 
     def pre_callback(self, ldap, dn, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         attrs_list.append('objectclass')
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.handle_iparangetype(entry_attrs, options)
         return dn
 
@@ -153,10 +158,12 @@ class range_mod(LDAPUpdate):
     msg_summary = _('Modified ID range "%(value)s"')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         attrs_list.append('objectclass')
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.handle_iparangetype(entry_attrs, options)
         return dn
 
@@ -166,4 +173,3 @@ api.register(range_mod)
 api.register(range_del)
 api.register(range_find)
 api.register(range_show)
-
diff --git a/ipalib/plugins/selinuxusermap.py b/ipalib/plugins/selinuxusermap.py
index 160e68c96..988cb4f0b 100644
--- a/ipalib/plugins/selinuxusermap.py
+++ b/ipalib/plugins/selinuxusermap.py
@@ -234,6 +234,7 @@ class selinuxusermap_add(LDAPCreate):
     msg_summary = _('Added SELinux User Map "%(value)s"')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         # rules are enabled by default
         entry_attrs['ipaenabledflag'] = 'TRUE'
         validate_selinuxuser_inlist(ldap, entry_attrs['ipaselinuxuser'])
@@ -243,6 +244,7 @@ class selinuxusermap_add(LDAPCreate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj._convert_seealso(ldap, entry_attrs, **options)
 
         return dn
@@ -264,6 +266,7 @@ class selinuxusermap_mod(LDAPUpdate):
     msg_summary = _('Modified SELinux User Map "%(value)s"')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (_dn, _entry_attrs) = ldap.get_entry(dn, attrs_list)
         except errors.NotFound:
@@ -288,6 +291,7 @@ class selinuxusermap_mod(LDAPUpdate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj._convert_seealso(ldap, entry_attrs, **options)
         return dn
 
@@ -331,6 +335,7 @@ class selinuxusermap_show(LDAPRetrieve):
     __doc__ = _('Display the properties of a SELinux User Map rule.')
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj._convert_seealso(ldap, entry_attrs, **options)
         return dn
 
@@ -398,6 +403,7 @@ class selinuxusermap_add_user(LDAPAddMember):
     member_count_out = ('%i object added.', '%i objects added.')
 
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (dn, entry_attrs) = ldap.get_entry(dn, self.obj.default_attributes)
         except errors.NotFound:
@@ -428,6 +434,7 @@ class selinuxusermap_add_host(LDAPAddMember):
     member_count_out = ('%i object added.', '%i objects added.')
 
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (dn, entry_attrs) = ldap.get_entry(dn, self.obj.default_attributes)
         except errors.NotFound:
diff --git a/ipalib/plugins/service.py b/ipalib/plugins/service.py
index 7cb7b8030..213711ab3 100644
--- a/ipalib/plugins/service.py
+++ b/ipalib/plugins/service.py
@@ -278,6 +278,7 @@ class service_add(LDAPCreate):
         ),
     )
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         (service, hostname, realm) = split_principal(keys[-1])
         if service.lower() == 'host' and not options['force']:
             raise errors.HostService()
@@ -322,6 +323,7 @@ class service_del(LDAPDelete):
     msg_summary = _('Deleted service "%(value)s"')
     member_attributes = ['managedby']
     def pre_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         # In the case of services we don't want IPA master services to be
         # deleted. This is a limited few though. If the user has their own
         # custom services allow them to manage them.
@@ -367,6 +369,7 @@ class service_mod(LDAPUpdate):
     member_attributes = ['managedby']
 
     def pre_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         if 'usercertificate' in options:
             (service, hostname, realm) = split_principal(keys[-1])
             cert = options.get('usercertificate')
@@ -386,7 +389,9 @@ class service_mod(LDAPUpdate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         set_certificate_attrs(entry_attrs)
+        return dn
 
 api.register(service_mod)
 
@@ -402,6 +407,7 @@ class service_find(LDAPSearch):
     has_output_params = LDAPSearch.has_output_params + output_params
 
     def pre_callback(self, ldap, filter, attrs_list, base_dn, scope, *args, **options):
+        assert isinstance(base_dn, DN)
         # lisp style!
         custom_filter = '(&(objectclass=ipaService)' \
                           '(!(objectClass=posixAccount))' \
@@ -439,6 +445,7 @@ class service_show(LDAPRetrieve):
     has_output_params = LDAPRetrieve.has_output_params + output_params
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.get_password_attributes(ldap, dn, entry_attrs)
 
         set_certificate_attrs(entry_attrs)
diff --git a/ipalib/plugins/sudorule.py b/ipalib/plugins/sudorule.py
index 723cce2e4..e2937949b 100644
--- a/ipalib/plugins/sudorule.py
+++ b/ipalib/plugins/sudorule.py
@@ -246,6 +246,7 @@ class sudorule_add(LDAPCreate):
     __doc__ = _('Create new Sudo Rule.')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         self.obj.check_order_uniqueness(*keys, **options)
         # Sudo Rules are enabled by default
         entry_attrs['ipaenabledflag'] = 'TRUE'
@@ -269,6 +270,7 @@ class sudorule_mod(LDAPUpdate):
 
     msg_summary = _('Modified Sudo Rule "%(value)s"')
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         if 'sudoorder' in options:
             new_order = options.get('sudoorder')
             old_entry = self.api.Command.sudorule_show(keys[-1])['result']
@@ -371,6 +373,7 @@ class sudorule_add_allow_command(LDAPAddMember):
     member_count_out = ('%i object added.', '%i objects added.')
 
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (_dn, _entry_attrs) = ldap.get_entry(dn, self.obj.default_attributes)
         except errors.NotFound:
@@ -399,6 +402,7 @@ class sudorule_add_deny_command(LDAPAddMember):
     member_count_out = ('%i object added.', '%i objects added.')
 
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (_dn, _entry_attrs) = ldap.get_entry(dn, self.obj.default_attributes)
         except errors.NotFound:
@@ -426,6 +430,7 @@ class sudorule_add_user(LDAPAddMember):
     member_count_out = ('%i object added.', '%i objects added.')
 
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (_dn, _entry_attrs) = ldap.get_entry(dn, self.obj.default_attributes)
         except errors.NotFound:
@@ -435,6 +440,7 @@ class sudorule_add_user(LDAPAddMember):
         return add_external_pre_callback('user', ldap, dn, keys, options)
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return add_external_post_callback('memberuser', 'user', 'externaluser', ldap, completed, failed, dn, entry_attrs, keys, options)
 
 api.register(sudorule_add_user)
@@ -447,6 +453,7 @@ class sudorule_remove_user(LDAPRemoveMember):
     member_count_out = ('%i object removed.', '%i objects removed.')
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return remove_external_post_callback('memberuser', 'user', 'externaluser', ldap, completed, failed, dn, entry_attrs, keys, options)
 
 api.register(sudorule_remove_user)
@@ -459,6 +466,7 @@ class sudorule_add_host(LDAPAddMember):
     member_count_out = ('%i object added.', '%i objects added.')
 
     def pre_callback(self, ldap, dn, found, not_found, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             (_dn, _entry_attrs) = ldap.get_entry(dn, self.obj.default_attributes)
         except errors.NotFound:
@@ -468,6 +476,7 @@ class sudorule_add_host(LDAPAddMember):
         return add_external_pre_callback('host', ldap, dn, keys, options)
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return add_external_post_callback('memberhost', 'host', 'externalhost', ldap, completed, failed, dn, entry_attrs, keys, options)
 
 api.register(sudorule_add_host)
@@ -480,6 +489,7 @@ class sudorule_remove_host(LDAPRemoveMember):
     member_count_out = ('%i object removed.', '%i objects removed.')
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return remove_external_post_callback('memberhost', 'host', 'externalhost', ldap, completed, failed, dn, entry_attrs, keys, options)
 
 api.register(sudorule_remove_host)
@@ -491,6 +501,7 @@ class sudorule_add_runasuser(LDAPAddMember):
     member_count_out = ('%i object added.', '%i objects added.')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         def check_validity(runas):
             v = unicode(runas)
             if v.upper() == u'ALL':
@@ -521,6 +532,7 @@ class sudorule_add_runasuser(LDAPAddMember):
         return add_external_pre_callback('user', ldap, dn, keys, options)
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return add_external_post_callback('ipasudorunas', 'user', 'ipasudorunasextuser', ldap, completed, failed, dn, entry_attrs, keys, options)
 
 api.register(sudorule_add_runasuser)
@@ -533,6 +545,7 @@ class sudorule_remove_runasuser(LDAPRemoveMember):
     member_count_out = ('%i object removed.', '%i objects removed.')
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return remove_external_post_callback('ipasudorunas', 'user', 'ipasudorunasextuser', ldap, completed, failed, dn, entry_attrs, keys, options)
 
 api.register(sudorule_remove_runasuser)
@@ -545,6 +558,7 @@ class sudorule_add_runasgroup(LDAPAddMember):
     member_count_out = ('%i object added.', '%i objects added.')
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         def check_validity(runas):
             v = unicode(runas)
             if v.upper() == u'ALL':
@@ -569,6 +583,7 @@ class sudorule_add_runasgroup(LDAPAddMember):
         return add_external_pre_callback('group', ldap, dn, keys, options)
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return add_external_post_callback('ipasudorunasgroup', 'group', 'ipasudorunasextgroup', ldap, completed, failed, dn, entry_attrs, keys, options)
 
 api.register(sudorule_add_runasgroup)
@@ -581,6 +596,7 @@ class sudorule_remove_runasgroup(LDAPRemoveMember):
     member_count_out = ('%i object removed.', '%i objects removed.')
 
     def post_callback(self, ldap, completed, failed, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         return remove_external_post_callback('ipasudorunasgroup', 'group', 'ipasudorunasextgroup', ldap, completed, failed, dn, entry_attrs, keys, options)
 
 api.register(sudorule_remove_runasgroup)
diff --git a/ipalib/plugins/trust.py b/ipalib/plugins/trust.py
index acb65b388..a70293bff 100644
--- a/ipalib/plugins/trust.py
+++ b/ipalib/plugins/trust.py
@@ -107,9 +107,10 @@ class trust(LDAPObject):
     )
 
 def make_trust_dn(env, trust_type, dn):
+    assert isinstance(dn, DN)
     if trust_type in trust.trust_types:
         container_dn = DN(('cn', trust_type), env.container_trusts, env.basedn)
-        return unicode(DN(DN(dn)[0], container_dn))
+        return DN(dn[0], container_dn)
     return dn
 
 class trust_add(LDAPCreate):
@@ -214,6 +215,7 @@ class trust_del(LDAPDelete):
     msg_summary = _('Deleted trust "%(value)s"')
 
     def pre_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         try:
             result = self.api.Command.trust_show(keys[-1])
         except errors.NotFound, e:
@@ -226,6 +228,7 @@ class trust_mod(LDAPUpdate):
     msg_summary = _('Modified trust "%(value)s"')
 
     def pre_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         result = None
         try:
             result = self.api.Command.trust_show(keys[-1])
@@ -245,6 +248,7 @@ class trust_find(LDAPSearch):
     # Since all trusts types are stored within separate containers under 'cn=trusts',
     # search needs to be done on a sub-tree scope
     def pre_callback(self, ldap, filters, attrs_list, base_dn, scope, *args, **options):
+        assert isinstance(base_dn, DN)
         return (filters, base_dn, ldap.SCOPE_SUBTREE)
 
 class trust_show(LDAPRetrieve):
@@ -271,6 +275,7 @@ class trust_show(LDAPRetrieve):
         return result
 
     def pre_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         if 'trust_show_type' in options:
             return make_trust_dn(self.env, options['trust_show_type'], dn)
         return dn
@@ -281,4 +286,3 @@ api.register(trust_mod)
 api.register(trust_del)
 api.register(trust_find)
 api.register(trust_show)
-
diff --git a/ipalib/plugins/user.py b/ipalib/plugins/user.py
index c19d9a666..529699f9a 100644
--- a/ipalib/plugins/user.py
+++ b/ipalib/plugins/user.py
@@ -375,11 +375,12 @@ class user(LDAPObject):
         if not manager:
             return None
 
-        if isinstance(manager, basestring):
+        if not isinstance(manager, list):
             manager = [manager]
         try:
+            container_dn = DN(self.container_dn, api.env.basedn)
             for m in xrange(len(manager)):
-                if manager[m].endswith('%s,%s' % (self.container_dn, api.env.basedn)):
+                if isinstance(manager[m], DN) and manager[m].endswith(container_dn):
                     continue
                 (dn, entry_attrs) = self.backend.find_entry_by_attr(
                         self.primary_key.name, manager[m], self.object_class, [''],
@@ -420,6 +421,7 @@ class user_add(LDAPCreate):
     )
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         if not options.get('noprivate', False):
             try:
                 # The Managed Entries plugin will allow a user to be created
@@ -459,7 +461,9 @@ class user_add(LDAPCreate):
             homes_root = config.get('ipahomesrootdir', ['/home'])[0]
             # build user's home directory based on his uid
             entry_attrs['homedirectory'] = posixpath.join(homes_root, keys[-1])
-        entry_attrs.setdefault('krbpwdpolicyreference', 'cn=global_policy,cn=%s,cn=kerberos,%s' % (api.env.realm, api.env.basedn))
+        entry_attrs.setdefault('krbpwdpolicyreference',
+                               DN(('cn', 'global_policy'), ('cn', api.env.realm), ('cn', 'kerberos'),
+                                  api.env.basedn))
         entry_attrs.setdefault('krbprincipalname', '%s@%s' % (entry_attrs['uid'], api.env.realm))
 
         if entry_attrs.get('gidnumber', DNA_MAGIC) == DNA_MAGIC:
@@ -496,6 +500,7 @@ class user_add(LDAPCreate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         config = ldap.get_ipa_config()[1]
         # add the user we just created into the default primary group
         def_primary_group = config.get('ipadefaultprimarygroup')
@@ -544,6 +549,7 @@ class user_del(LDAPDelete):
     msg_summary = _('Deleted user "%(value)s"')
 
     def pre_callback(self, ldap, dn, *keys, **options):
+        assert isinstance(dn, DN)
         protected_group_name = u'admins'
         result = api.Command.group_show(protected_group_name)
         if result['result'].get('member_user', []) == [keys[-1]]:
@@ -562,6 +568,7 @@ class user_mod(LDAPUpdate):
     has_output_params = LDAPUpdate.has_output_params + user_output_params
 
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
+        assert isinstance(dn, DN)
         if options.get('rename') is not None:
             config = ldap.get_ipa_config()[1]
             if 'ipamaxusernamelength' in config:
@@ -592,6 +599,7 @@ class user_mod(LDAPUpdate):
         return dn
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         if options.get('random', False):
             try:
                 entry_attrs['randompassword'] = unicode(getattr(context, 'randompassword'))
@@ -621,6 +629,7 @@ class user_find(LDAPSearch):
     )
 
     def pre_callback(self, ldap, filter, attrs_list, base_dn, scope, *keys, **options):
+        assert isinstance(base_dn, DN)
         if options.get('whoami'):
             return ("(&(objectclass=posixaccount)(krbprincipalname=%s))"%\
                         getattr(context, 'principal'), base_dn, scope)
@@ -651,6 +660,7 @@ class user_show(LDAPRetrieve):
     has_output_params = LDAPRetrieve.has_output_params + user_output_params
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
+        assert isinstance(dn, DN)
         convert_nsaccountlock(entry_attrs)
         self.obj._convert_manager(entry_attrs, **options)
         self.obj.get_password_attributes(ldap, dn, entry_attrs)
@@ -763,7 +773,7 @@ class user_status(LDAPQuery):
         # Get list of masters
         try:
             (masters, truncated) = ldap.find_entries(
-                None, ['*'], 'cn=masters,cn=ipa,cn=etc,%s' % api.env.basedn,
+                None, ['*'], DN(('cn', 'masters'), ('cn', 'ipa'), ('cn', 'etc'), api.env.basedn),
                 ldap.SCOPE_ONELEVEL
             )
         except errors.NotFound:
diff --git a/ipalib/plugins/virtual.py b/ipalib/plugins/virtual.py
index c827d3d9d..8db1a9653 100644
--- a/ipalib/plugins/virtual.py
+++ b/ipalib/plugins/virtual.py
@@ -23,6 +23,7 @@ Base classes for non-LDAP backend plugins.
 from ipalib import api
 from ipalib import Command
 from ipalib import errors
+from ipapython.dn import DN
 
 class VirtualCommand(Command):
     """
@@ -55,7 +56,7 @@ class VirtualCommand(Command):
         ldap = self.api.Backend.ldap2
         self.log.debug("IPA: virtual verify %s" % operation)
 
-        operationdn = "cn=%s,%s,%s" % (operation, self.api.env.container_virtual, self.api.env.basedn)
+        operationdn = DN(('cn', operation), self.api.env.container_virtual, self.api.env.basedn)
 
         try:
             if not ldap.can_write(operationdn, "objectclass"):