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@@ -0,0 +1,1576 @@ +<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" []> +<!-- + - Copyright (C) 2004-2008 Internet Systems Consortium, Inc. ("ISC") + - Copyright (C) 2000-2003 Internet Software Consortium. + - + - Permission to use, copy, modify, and/or distribute this software for any + - purpose with or without fee is hereby granted, provided that the above + - copyright notice and this permission notice appear in all copies. + - + - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH + - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY + - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, + - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE + - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + - PERFORMANCE OF THIS SOFTWARE. +--> + +<!-- $Id: FAQ.xml,v 1.46 2008/09/09 05:42:17 marka Exp $ --> + +<article class="faq"> + <title>Frequently Asked Questions about BIND 9</title> + <articleinfo> + <copyright> + <year>2004</year> + <year>2005</year> + <year>2006</year> + <year>2007</year> + <year>2008</year> + <holder>Internet Systems Consortium, Inc. ("ISC")</holder> + </copyright> + <copyright> + <year>2000</year> + <year>2001</year> + <year>2002</year> + <year>2003</year> + <holder>Internet Software Consortium.</holder> + </copyright> + </articleinfo> + <qandaset defaultlabel='qanda'> + + <qandadiv><title>Compilation and Installation Questions</title> + + <qandaentry> + <question> + <para> + I'm trying to compile BIND 9, and "make" is failing due to + files not being found. Why? + </para> + </question> + <answer> + <para> + Using a parallel or distributed "make" to build BIND 9 is + not supported, and doesn't work. If you are using one of + these, use normal make or gmake instead. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + Isn't "make install" supposed to generate a default named.conf? + </para> + </question> + <answer> + <para> + Short Answer: No. + </para> + <para> + Long Answer: There really isn't a default configuration which fits + any site perfectly. There are lots of decisions that need to + be made and there is no consensus on what the defaults should be. + For example FreeBSD uses /etc/namedb as the location where the + configuration files for named are stored. Others use /var/named. + </para> + <para> + What addresses to listen on? For a laptop on the move a lot + you may only want to listen on the loop back interfaces. + </para> + <para> + Who do you offer recursive service to? Is there are firewall + to consider? If so is it stateless or stateful. Are you + directly on the Internet? Are you on a private network? Are + you on a NAT'd network? The answers + to all these questions change how you configure even a + caching name server. + </para> + </answer> + </qandaentry> + + </qandadiv> <!-- Compilation and Installation Questions --> + + <qandadiv><title>Configuration and Setup Questions</title> + + <qandaentry> + <!-- configuration, log --> + <question> + <para> + Why does named log the warning message <quote>no TTL specified - + using SOA MINTTL instead</quote>? + </para> + </question> + <answer> + <para> + Your zone file is illegal according to RFC1035. It must either + have a line like: + </para> + <informalexample> + <programlisting> +$TTL 86400</programlisting> + </informalexample> + <para> + at the beginning, or the first record in it must have a TTL field, + like the "84600" in this example: + </para> + <informalexample> + <programlisting> +example.com. 86400 IN SOA ns hostmaster ( 1 3600 1800 1814400 3600 )</programlisting> + </informalexample> + </answer> + </qandaentry> + + <qandaentry> + <!-- configuration --> + <question> + <para> + Why do I get errors like <quote>dns_zone_load: zone foo/IN: loading + master file bar: ran out of space</quote>? + </para> + </question> + <answer> + <para> + This is often caused by TXT records with missing close + quotes. Check that all TXT records containing quoted strings + have both open and close quotes. + </para> + </answer> + </qandaentry> + + <qandaentry> + <!-- security --> + <question> + <para> + How do I restrict people from looking up the server version? + </para> + </question> + <answer> + <para> + Put a "version" option containing something other than the + real version in the "options" section of named.conf. Note + doing this will not prevent attacks and may impede people + trying to diagnose problems with your server. Also it is + possible to "fingerprint" nameservers to determine their + version. + </para> + </answer> + </qandaentry> + + <qandaentry> + <!-- security --> + <question> + <para> + How do I restrict only remote users from looking up the + server version? + </para> + </question> + <answer> + <para> + The following view statement will intercept lookups as the + internal view that holds the version information will be + matched last. The caveats of the previous answer still + apply, of course. + </para> + <informalexample> + <programlisting> +view "chaos" chaos { + match-clients { <those to be refused>; }; + allow-query { none; }; + zone "." { + type hint; + file "/dev/null"; // or any empty file + }; +};</programlisting> + </informalexample> + </answer> + </qandaentry> + + <qandaentry> + <!-- configuration --> + <question> + <para> + What do <quote>no source of entropy found</quote> or <quote>could not + open entropy source foo</quote> mean? + </para> + </question> + <answer> + <para> + The server requires a source of entropy to perform certain + operations, mostly DNSSEC related. These messages indicate + that you have no source of entropy. On systems with + /dev/random or an equivalent, it is used by default. A + source of entropy can also be defined using the random-device + option in named.conf. + </para> + </answer> + </qandaentry> + + <qandaentry> + <!-- configuration --> + <question> + <para> + I'm trying to use TSIG to authenticate dynamic updates or + zone transfers. I'm sure I have the keys set up correctly, + but the server is rejecting the TSIG. Why? + </para> + </question> + <answer> + <para> + This may be a clock skew problem. Check that the the clocks + on the client and server are properly synchronised (e.g., + using ntp). + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I see a log message like the following. Why? + </para> + <para> + couldn't open pid file '/var/run/named.pid': Permission denied + </para> + </question> + <answer> + <para> + You are most likely running named as a non-root user, and + that user does not have permission to write in /var/run. + The common ways of fixing this are to create a /var/run/named + directory owned by the named user and set pid-file to + "/var/run/named/named.pid", or set pid-file to "named.pid", + which will put the file in the directory specified by the + directory option (which, in this case, must be writable by + the named user). + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I can query the nameserver from the nameserver but not from other + machines. Why? + </para> + </question> + <answer> + <para> + This is usually the result of the firewall configuration stopping + the queries and / or the replies. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + How can I make a server a slave for both an internal and + an external view at the same time? When I tried, both views + on the slave were transferred from the same view on the master. + </para> + </question> + <answer> + <para> + You will need to give the master and slave multiple IP + addresses and use those to make sure you reach the correct + view on the other machine. + </para> + <informalexample> + <programlisting> +Master: 10.0.1.1 (internal), 10.0.1.2 (external, IP alias) + internal: + match-clients { !10.0.1.2; !10.0.1.4; 10.0.1/24; }; + notify-source 10.0.1.1; + transfer-source 10.0.1.1; + query-source address 10.0.1.1; + external: + match-clients { any; }; + recursion no; // don't offer recursion to the world + notify-source 10.0.1.2; + transfer-source 10.0.1.2; + query-source address 10.0.1.2; + +Slave: 10.0.1.3 (internal), 10.0.1.4 (external, IP alias) + internal: + match-clients { !10.0.1.2; !10.0.1.4; 10.0.1/24; }; + notify-source 10.0.1.3; + transfer-source 10.0.1.3; + query-source address 10.0.1.3; + external: + match-clients { any; }; + recursion no; // don't offer recursion to the world + notify-source 10.0.1.4; + transfer-source 10.0.1.4; + query-source address 10.0.1.4;</programlisting> + </informalexample> + <para> + You put the external address on the alias so that all the other + dns clients on these boxes see the internal view by default. + </para> + </answer> + <answer> + <para> + BIND 9.3 and later: Use TSIG to select the appropriate view. + </para> + <informalexample> + <programlisting> +Master 10.0.1.1: + key "external" { + algorithm hmac-md5; + secret "xxxxxxxx"; + }; + view "internal" { + match-clients { !key external; 10.0.1/24; }; + ... + }; + view "external" { + match-clients { key external; any; }; + server 10.0.1.2 { keys external; }; + recursion no; + ... + }; + +Slave 10.0.1.2: + key "external" { + algorithm hmac-md5; + secret "xxxxxxxx"; + }; + view "internal" { + match-clients { !key external; 10.0.1/24; }; + ... + }; + view "external" { + match-clients { key external; any; }; + server 10.0.1.1 { keys external; }; + recursion no; + ... + };</programlisting> + </informalexample> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I get error messages like <quote>multiple RRs of singleton type</quote> + and <quote>CNAME and other data</quote> when transferring a zone. What + does this mean? + </para> + </question> + <answer> + <para> + These indicate a malformed master zone. You can identify + the exact records involved by transferring the zone using + dig then running named-checkzone on it. + </para> + <informalexample> + <programlisting> +dig axfr example.com @master-server > tmp +named-checkzone example.com tmp</programlisting> + </informalexample> + <para> + A CNAME record cannot exist with the same name as another record + except for the DNSSEC records which prove its existence (NSEC). + </para> + <para> + RFC 1034, Section 3.6.2: <quote>If a CNAME RR is present at a node, + no other data should be present; this ensures that the data for a + canonical name and its aliases cannot be different. This rule also + insures that a cached CNAME can be used without checking with an + authoritative server for other RR types.</quote> + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I get error messages like <quote>named.conf:99: unexpected end + of input</quote> where 99 is the last line of named.conf. + </para> + </question> + <answer> + <para> + There are unbalanced quotes in named.conf. + </para> + </answer> + <answer> + <para> + Some text editors (notepad and wordpad) fail to put a line + title indication (e.g. CR/LF) on the last line of a + text file. This can be fixed by "adding" a blank line to + the end of the file. Named expects to see EOF immediately + after EOL and treats text files where this is not met as + truncated. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + How do I share a dynamic zone between multiple views? + </para> + </question> + <answer> + <para> + You choose one view to be master and the second a slave and + transfer the zone between views. + </para> + <informalexample> + <programlisting> +Master 10.0.1.1: + key "external" { + algorithm hmac-md5; + secret "xxxxxxxx"; + }; + + key "mykey" { + algorithm hmac-md5; + secret "yyyyyyyy"; + }; + + view "internal" { + match-clients { !key external; 10.0.1/24; }; + server 10.0.1.1 { + /* Deliver notify messages to external view. */ + keys { external; }; + }; + zone "example.com" { + type master; + file "internal/example.db"; + allow-update { key mykey; }; + notify-also { 10.0.1.1; }; + }; + }; + + view "external" { + match-clients { key external; any; }; + zone "example.com" { + type slave; + file "external/example.db"; + masters { 10.0.1.1; }; + transfer-source { 10.0.1.1; }; + // allow-update-forwarding { any; }; + // allow-notify { ... }; + }; + };</programlisting> + </informalexample> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I get a error message like <quote>zone wireless.ietf56.ietf.org/IN: + loading master file primaries/wireless.ietf56.ietf.org: no + owner</quote>. + </para> + </question> + <answer> + <para> + This error is produced when a line in the master file + contains leading white space (tab/space) but the is no + current record owner name to inherit the name from. Usually + this is the result of putting white space before a comment, + forgetting the "@" for the SOA record, or indenting the master + file. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + Why are my logs in GMT (UTC). + </para> + </question> + <answer> + <para> + You are running chrooted (-t) and have not supplied local timezone + information in the chroot area. + </para> + <simplelist> + <member>FreeBSD: /etc/localtime</member> + <member>Solaris: /etc/TIMEZONE and /usr/share/lib/zoneinfo</member> + <member>OSF: /etc/zoneinfo/localtime</member> + </simplelist> + <para> + See also tzset(3) and zic(8). + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I get <quote>rndc: connect failed: connection refused</quote> when + I try to run rndc. + </para> + </question> + <answer> + <para> + This is usually a configuration error. + </para> + <para> + First ensure that named is running and no errors are being + reported at startup (/var/log/messages or equivalent). + Running "named -g <usual arguments>" from a title + can help at this point. + </para> + <para> + Secondly ensure that named is configured to use rndc either + by "rndc-confgen -a", rndc-confgen or manually. The + Administrators Reference manual has details on how to do + this. + </para> + <para> + Old versions of rndc-confgen used localhost rather than + 127.0.0.1 in /etc/rndc.conf for the default server. Update + /etc/rndc.conf if necessary so that the default server + listed in /etc/rndc.conf matches the addresses used in + named.conf. "localhost" has two address (127.0.0.1 and + ::1). + </para> + <para> + If you use "rndc-confgen -a" and named is running with -t or -u + ensure that /etc/rndc.conf has the correct ownership and that + a copy is in the chroot area. You can do this by re-running + "rndc-confgen -a" with appropriate -t and -u arguments. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I get <quote>transfer of 'example.net/IN' from 192.168.4.12#53: + failed while receiving responses: permission denied</quote> error + messages. + </para> + </question> + <answer> + <para> + These indicate a filesystem permission error preventing + named creating / renaming the temporary file. These will + usually also have other associated error messages like + </para> + <informalexample> + <programlisting> +"dumping master file: sl/tmp-XXXX5il3sQ: open: permission denied"</programlisting> + </informalexample> + <para> + Named needs write permission on the directory containing + the file. Named writes the new cache file to a temporary + file then renames it to the name specified in named.conf + to ensure that the contents are always complete. This is + to prevent named loading a partial zone in the event of + power failure or similar interrupting the write of the + master file. + </para> + <para> + Note file names are relative to the directory specified in + options and any chroot directory ([<chroot + dir>/][<options dir>]). + </para> + <informalexample> + <para> + If named is invoked as "named -t /chroot/DNS" with + the following named.conf then "/chroot/DNS/var/named/sl" + needs to be writable by the user named is running as. + </para> + <programlisting> +options { + directory "/var/named"; +}; + +zone "example.net" { + type slave; + file "sl/example.net"; + masters { 192.168.4.12; }; +};</programlisting> + </informalexample> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I want to forward all DNS queries from my caching nameserver to + another server. But there are some domains which have to be + served locally, via rbldnsd. + </para> + <para> + How do I achieve this ? + </para> + </question> + <answer> + <programlisting> +options { + forward only; + forwarders { <ip.of.primary.nameserver>; }; +}; + +zone "sbl-xbl.spamhaus.org" { + type forward; forward only; + forwarders { <ip.of.rbldns.server> port 530; }; +}; + +zone "list.dsbl.org" { + type forward; forward only; + forwarders { <ip.of.rbldns.server> port 530; }; +}; + </programlisting> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + Can you help me understand how BIND 9 uses memory to store + DNS zones? + </para> + <para> + Some times it seems to take several times the amount of + memory it needs to store the zone. + </para> + </question> + <answer> + <para> + When reloading a zone named my have multiple copies of + the zone in memory at one time. The zone it is serving + and the one it is loading. If reloads are ultra fast it + can have more still. + </para> + <para> + e.g. Ones that are transferring out, the one that it is + serving and the one that is loading. + </para> + <para> + BIND 8 destroyed the zone before loading and also killed + off outgoing transfers of the zone. + </para> + <para> + The new strategy allows slaves to get copies of the new + zone regardless of how often the master is loaded compared + to the transfer time. The slave might skip some intermediate + versions but the transfers will complete and it will keep + reasonably in sync with the master. + </para> + <para> + The new strategy also allows the master to recover from + syntax and other errors in the master file as it still + has an in-core copy of the old contents. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I want to use IPv6 locally but I don't have a external IPv6 + connection. External lookups are slow. + </para> + </question> + <answer> + <para> + You can use server clauses to stop named making external lookups + over IPv6. + </para> + <programlisting> +server fd81:ec6c:bd62::/48 { bogus no; }; // site ULA prefix +server ::/0 { bogus yes; }; +</programlisting> + </answer> + </qandaentry> + + </qandadiv> <!-- Configuration and Setup Questions --> + + <qandadiv><title>Operations Questions</title> + + <qandaentry> + <question> + <para> + How to change the nameservers for a zone? + </para> + </question> + <answer> + <para> + Step 1: Ensure all nameservers, new and old, are serving the + same zone content. + </para> + <para> + Step 2: Work out the maximum TTL of the NS RRset in the parent and child + zones. This is the time it will take caches to be clear of a + particular version of the NS RRset. + If you are just removing nameservers you can skip to Step 6. + </para> + <para> + Step 3: Add new nameservers to the NS RRset for the zone and + wait until all the servers for the zone are answering with this + new NS RRset. + </para> + <para> + Step 4: Inform the parent zone of the new NS RRset then wait for all the + parent servers to be answering with the new NS RRset. + </para> + <para> + Step 5: Wait for cache to be clear of the old NS RRset. + See Step 2 for how long. + If you are just adding nameservers you are done. + </para> + <para> + Step 6: Remove any old nameservers from the zones NS RRset and + wait for all the servers for the zone to be serving the new NS RRset. + </para> + <para> + Step 7: Inform the parent zone of the new NS RRset then wait for all the + parent servers to be answering with the new NS RRset. + </para> + <para> + Step 8: Wait for cache to be clear of the old NS RRset. + See Step 2 for how long. + </para> + <para> + Step 9: Turn off the old nameservers or remove the zone entry from + the configuration of the old nameservers. + </para> + <para> + Step 10: Increment the serial number and wait for the change to + be visible in all nameservers for the zone. This ensures that + zone transfers are still working after the old servers are + decommissioned. + </para> + <para> + Note: the above procedure is designed to be transparent + to dns clients. Decommissioning the old servers too early + will result in some clients not being able to look up + answers in the zone. + </para> + <para> + Note: while it is possible to run the addition and removal + stages together it is not recommended. + </para> + </answer> + </qandaentry> + + </qandadiv> <!-- Operations Questions --> + + <qandadiv><title>General Questions</title> + + <qandaentry> + <question> + <para> + I keep getting log messages like the following. Why? + </para> + <para> + Dec 4 23:47:59 client 10.0.0.1#1355: updating zone + 'example.com/IN': update failed: 'RRset exists (value + dependent)' prerequisite not satisfied (NXRRSET) + </para> + </question> + <answer> + <para> + DNS updates allow the update request to test to see if + certain conditions are met prior to proceeding with the + update. The message above is saying that conditions were + not met and the update is not proceeding. See doc/rfc/rfc2136.txt + for more details on prerequisites. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I keep getting log messages like the following. Why? + </para> + <para> + Jun 21 12:00:00.000 client 10.0.0.1#1234: update denied + </para> + </question> + <answer> + <para> + Someone is trying to update your DNS data using the RFC2136 + Dynamic Update protocol. Windows 2000 machines have a habit + of sending dynamic update requests to DNS servers without + being specifically configured to do so. If the update + requests are coming from a Windows 2000 machine, see + <ulink + url="http://support.microsoft.com/support/kb/articles/q246/8/04.asp"> + <http://support.microsoft.com/support/kb/articles/q246/8/04.asp></ulink> + for information about how to turn them off. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + When I do a "dig . ns", many of the A records for the root + servers are missing. Why? + </para> + </question> + <answer> + <para> + This is normal and harmless. It is a somewhat confusing + side effect of the way BIND 9 does RFC2181 trust ranking + and of the efforts BIND 9 makes to avoid promoting glue + into answers. + </para> + <para> + When BIND 9 first starts up and primes its cache, it receives + the root server addresses as additional data in an authoritative + response from a root server, and these records are eligible + for inclusion as additional data in responses. Subsequently + it receives a subset of the root server addresses as + additional data in a non-authoritative (referral) response + from a root server. This causes the addresses to now be + considered non-authoritative (glue) data, which is not + eligible for inclusion in responses. + </para> + <para> + The server does have a complete set of root server addresses + cached at all times, it just may not include all of them + as additional data, depending on whether they were last + received as answers or as glue. You can always look up the + addresses with explicit queries like "dig a.root-servers.net A". + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + Why don't my zones reload when I do an "rndc reload" or SIGHUP? + </para> + </question> + <answer> + <para> + A zone can be updated either by editing zone files and + reloading the server or by dynamic update, but not both. + If you have enabled dynamic update for a zone using the + "allow-update" option, you are not supposed to edit the + zone file by hand, and the server will not attempt to reload + it. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + Why is named listening on UDP port other than 53? + </para> + </question> + <answer> + <para> + Named uses a system selected port to make queries of other + nameservers. This behaviour can be overridden by using + query-source to lock down the port and/or address. See + also notify-source and transfer-source. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I get warning messages like <quote>zone example.com/IN: refresh: + failure trying master 1.2.3.4#53: timed out</quote>. + </para> + </question> + <answer> + <para> + Check that you can make UDP queries from the slave to the master + </para> + <informalexample> + <programlisting> +dig +norec example.com soa @1.2.3.4</programlisting> + </informalexample> + <para> + You could be generating queries faster than the slave can + cope with. Lower the serial query rate. + </para> + <informalexample> + <programlisting> +serial-query-rate 5; // default 20</programlisting> + </informalexample> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I don't get RRSIG's returned when I use "dig +dnssec". + </para> + </question> + <answer> + <para> + You need to ensure DNSSEC is enabled (dnssec-enable yes;). + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + Can a NS record refer to a CNAME. + </para> + </question> + <answer> + <para> + No. The rules for glue (copies of the *address* records + in the parent zones) and additional section processing do + not allow it to work. + </para> + <para> + You would have to add both the CNAME and address records + (A/AAAA) as glue to the parent zone and have CNAMEs be + followed when doing additional section processing to make + it work. No nameserver implementation supports either of + these requirements. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + What does <quote>RFC 1918 response from Internet for + 0.0.0.10.IN-ADDR.ARPA</quote> mean? + </para> + </question> + <answer> + <para> + If the IN-ADDR.ARPA name covered refers to a internal address + space you are using then you have failed to follow RFC 1918 + usage rules and are leaking queries to the Internet. You + should establish your own zones for these addresses to prevent + you querying the Internet's name servers for these addresses. + Please see <ulink url="http://as112.net/"><http://as112.net/></ulink> + for details of the problems you are causing and the counter + measures that have had to be deployed. + </para> + <para> + If you are not using these private addresses then a client + has queried for them. You can just ignore the messages, + get the offending client to stop sending you these messages + as they are most probably leaking them or setup your own zones + empty zones to serve answers to these queries. + </para> + <informalexample> + <programlisting> +zone "10.IN-ADDR.ARPA" { + type master; + file "empty"; +}; + +zone "16.172.IN-ADDR.ARPA" { + type master; + file "empty"; +}; + +... + +zone "31.172.IN-ADDR.ARPA" { + type master; + file "empty"; +}; + +zone "168.192.IN-ADDR.ARPA" { + type master; + file "empty"; +}; + +empty: +@ 10800 IN SOA <name-of-server>. <contact-email>. ( + 1 3600 1200 604800 10800 ) +@ 10800 IN NS <name-of-server>.</programlisting> + </informalexample> + <para> + <note> + Future versions of named are likely to do this automatically. + </note> + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + Will named be affected by the 2007 changes to daylight savings + rules in the US. + </para> + </question> + <answer> + <para> + No, so long as the machines internal clock (as reported + by "date -u") remains at UTC. The only visible change + if you fail to upgrade your OS, if you are in a affected + area, will be that log messages will be a hour out during + the period where the old rules do not match the new rules. + </para> + <para> + For most OS's this change just means that you need to + update the conversion rules from UTC to local time. + Normally this involves updating a file in /etc (which + sets the default timezone for the machine) and possibly + a directory which has all the conversion rules for the + world (e.g. /usr/share/zoneinfo). When updating the OS + do not forget to update any chroot areas as well. + See your OS's documentation for more details. + </para> + <para> + The local timezone conversion rules can also be done on + a individual basis by setting the TZ environment variable + appropriately. See your OS's documentation for more + details. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + Is there a bugzilla (or other tool) database that mere + mortals can have (read-only) access to for bind? + </para> + </question> + <answer> + <para> + No. The BIND 9 bug database is kept closed for a number + of reasons. These include, but are not limited to, that + the database contains proprietory information from people + reporting bugs. The database has in the past and may in + future contain unfixed bugs which are capable of bringing + down most of the Internet's DNS infrastructure. + </para> + <para> + The release pages for each version contain up to date + lists of bugs that have been fixed post release. That + is as close as we can get to providing a bug database. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + Why do queries for NSEC3 records fail to return the NSEC3 record? + </para> + </question> + <answer> + <para> + NSEC3 records are strictly meta data and can only be + returned in the authority section. This is done so that + signing the zone using NSEC3 records does not bring names + into existance that do not exist in the unsigned version + of the zone. + </para> + </answer> + </qandaentry> + + </qandadiv> <!-- General Questions --> + + <qandadiv><title>Operating-System Specific Questions</title> + + <qandadiv><title>HPUX</title> + + <qandaentry> + <question> + <para>I get the following error trying to configure BIND: +<programlisting>checking if unistd.h or sys/types.h defines fd_set... no +configure: error: need either working unistd.h or sys/select.h</programlisting> + </para> + </question> + <answer> + <para> + You have attempted to configure BIND with the bundled C compiler. + This compiler does not meet the minimum compiler requirements to + for building BIND. You need to install a ANSI C compiler and / or + teach configure how to find the ANSI C compiler. The later can + be done by adjusting the PATH environment variable and / or + specifying the compiler via CC. + </para> + <informalexample> + <programlisting>./configure CC=<compiler> ...</programlisting> + </informalexample> + </answer> + </qandaentry> + + </qandadiv> <!-- HPUX --> + + <qandadiv><title>Linux</title> + + <qandaentry> + <question> + <para> + Why do I get the following errors: +<programlisting>general: errno2result.c:109: unexpected error: +general: unable to convert errno to isc_result: 14: Bad address +client: UDP client handler shutting down due to fatal receive error: unexpected error</programlisting> + </para> + </question> + <answer> + <para> + This is the result of a Linux kernel bug. + </para> + <para> + See: + <ulink url="http://marc.theaimsgroup.com/?l=linux-netdev&m=113081708031466&w=2"><http://marc.theaimsgroup.com/?l=linux-netdev&m=113081708031466&w=2></ulink> + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + Why does named lock up when it attempts to connect over IPSEC tunnels? + </para> + </question> + <answer> + <para> + This is due to a kernel bug where the fact that a socket is marked + non-blocking is ignored. It is reported that setting + xfrm_larval_drop to 1 helps but this may have negative side effects. + See: +<ulink url="https://bugzilla.redhat.com/show_bug.cgi?id=427629"><https://bugzilla.redhat.com/show_bug.cgi?id=427629></ulink> + and +<ulink url="http://lkml.org/lkml/2007/12/4/260"><http://lkml.org/lkml/2007/12/4/260></ulink>. + </para> + <para> + xfrm_larval_drop can be set to 1 by the following procedure: +<programlisting> +echo "1" > proc/sys/net/core/xfrm_larval_drop</programlisting> + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + Why do I see 5 (or more) copies of named on Linux? + </para> + </question> + <answer> + <para> + Linux threads each show up as a process under ps. The + approximate number of threads running is n+4, where n is + the number of CPUs. Note that the amount of memory used + is not cumulative; if each process is using 10M of memory, + only a total of 10M is used. + </para> + <para> + Newer versions of Linux's ps command hide the individual threads + and require -L to display them. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + Why does BIND 9 log <quote>permission denied</quote> errors accessing + its configuration files or zones on my Linux system even + though it is running as root? + </para> + </question> + <answer> + <para> + On Linux, BIND 9 drops most of its root privileges on + startup. This including the privilege to open files owned + by other users. Therefore, if the server is running as + root, the configuration files and zone files should also + be owned by root. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I get the error message <quote>named: capset failed: Operation + not permitted</quote> when starting named. + </para> + </question> + <answer> + <para> + The capability module, part of "Linux Security Modules/LSM", + has not been loaded into the kernel. See insmod(8), modprobe(8). + </para> + <para> + The relevant modules can be loaded by running: +<programlisting> +modprobe commoncap +modprobe capability</programlisting> + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I'm running BIND on Red Hat Enterprise Linux or Fedora Core - + </para> + <para> + Why can't named update slave zone database files? + </para> + <para> + Why can't named create DDNS journal files or update + the master zones from journals? + </para> + <para> + Why can't named create custom log files? + </para> + </question> + + <answer> + <para> + Red Hat Security Enhanced Linux (SELinux) policy security + protections : + </para> + + <para> + Red Hat have adopted the National Security Agency's + SELinux security policy (see <ulink + url="http://www.nsa.gov/selinux"><http://www.nsa.gov/selinux></ulink>) + and recommendations for BIND security , which are more + secure than running named in a chroot and make use of + the bind-chroot environment unnecessary . + </para> + + <para> + By default, named is not allowed by the SELinux policy + to write, create or delete any files EXCEPT in these + directories: + <informalexample> + <programlisting> +$ROOTDIR/var/named/slaves +$ROOTDIR/var/named/data +$ROOTDIR/var/tmp + </programlisting> + </informalexample> + where $ROOTDIR may be set in /etc/sysconfig/named if + bind-chroot is installed. + </para> + + <para> + The SELinux policy particularly does NOT allow named to modify + the $ROOTDIR/var/named directory, the default location for master + zone database files. + </para> + + <para> + SELinux policy overrules file access permissions - so + even if all the files under /var/named have ownership + named:named and mode rw-rw-r--, named will still not be + able to write or create files except in the directories + above, with SELinux in Enforcing mode. + </para> + + <para> + So, to allow named to update slave or DDNS zone files, + it is best to locate them in $ROOTDIR/var/named/slaves, + with named.conf zone statements such as: + <informalexample> + <programlisting> +zone "slave.zone." IN { + type slave; + file "slaves/slave.zone.db"; + ... +}; +zone "ddns.zone." IN { + type master; + allow-updates {...}; + file "slaves/ddns.zone.db"; +}; + </programlisting> + </informalexample> + </para> + + <para> + To allow named to create its cache dump and statistics + files, for example, you could use named.conf options + statements such as: + <informalexample> + <programlisting> +options { + ... + dump-file "/var/named/data/cache_dump.db"; + statistics-file "/var/named/data/named_stats.txt"; + ... +}; + </programlisting> + </informalexample> + </para> + + <para> + You can also tell SELinux to allow named to update any + zone database files, by setting the SELinux tunable boolean + parameter 'named_write_master_zones=1', using the + system-config-securitylevel GUI, using the 'setsebool' + command, or in /etc/selinux/targeted/booleans. + </para> + + <para> + You can disable SELinux protection for named entirely by + setting the 'named_disable_trans=1' SELinux tunable boolean + parameter. + </para> + + <para> + The SELinux named policy defines these SELinux contexts for named: + <informalexample> + <programlisting> +named_zone_t : for zone database files - $ROOTDIR/var/named/* +named_conf_t : for named configuration files - $ROOTDIR/etc/{named,rndc}.* +named_cache_t: for files modifiable by named - $ROOTDIR/var/{tmp,named/{slaves,data}} + </programlisting> + </informalexample> + </para> + + <para> + If you want to retain use of the SELinux policy for named, + and put named files in different locations, you can do + so by changing the context of the custom file locations + . + </para> + + <para> + To create a custom configuration file location, e.g. + '/root/named.conf', to use with the 'named -c' option, + do: + <informalexample> + <programlisting> +# chcon system_u:object_r:named_conf_t /root/named.conf + </programlisting> + </informalexample> + </para> + + <para> + To create a custom modifiable named data location, e.g. + '/var/log/named' for a log file, do: + <informalexample> + <programlisting> +# chcon system_u:object_r:named_cache_t /var/log/named + </programlisting> + </informalexample> + </para> + + <para> + To create a custom zone file location, e.g. /root/zones/, do: + <informalexample> + <programlisting> +# chcon system_u:object_r:named_zone_t /root/zones/{.,*} + </programlisting> + </informalexample> + </para> + + <para> + See these man-pages for more information : selinux(8), + named_selinux(8), chcon(1), setsebool(8) + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + Listening on individual IPv6 interfaces does not work. + </para> + </question> + <answer> + <para> + This is usually due to "/proc/net/if_inet6" not being available + in the chroot file system. Mount another instance of "proc" + in the chroot file system. + </para> + <para> + This can be be made permanent by adding a second instance to + /etc/fstab. + <informalexample> + <programlisting> +proc /proc proc defaults 0 0 +proc /var/named/proc proc defaults 0 0</programlisting> + </informalexample> + </para> + </answer> + </qandaentry> + + </qandadiv> <!-- Linux --> + + <qandadiv><title>Windows</title> + + <qandaentry> + <question> + <para> + Zone transfers from my BIND 9 master to my Windows 2000 + slave fail. Why? + </para> + </question> + <answer> + <para> + This may be caused by a bug in the Windows 2000 DNS server + where DNS messages larger than 16K are not handled properly. + This can be worked around by setting the option "transfer-format + one-answer;". Also check whether your zone contains domain + names with embedded spaces or other special characters, + like "John\032Doe\213s\032Computer", since such names have + been known to cause Windows 2000 slaves to incorrectly + reject the zone. + </para> + </answer> + </qandaentry> + + <qandaentry> + <question> + <para> + I get <quote>Error 1067</quote> when starting named under Windows. + </para> + </question> + <answer> + <para> + This is the service manager saying that named exited. You + need to examine the Application log in the EventViewer to + find out why. + </para> + <para> + Common causes are that you failed to create "named.conf" + (usually "C:\windows\dns\etc\named.conf") or failed to + specify the directory in named.conf. + </para> + <informalexample> + <programlisting> +options { + Directory "C:\windows\dns\etc"; +};</programlisting> + </informalexample> + </answer> + </qandaentry> + + </qandadiv> <!-- Windows --> + + <qandadiv><title>FreeBSD</title> + + <qandaentry> + <question> + <para> + I have FreeBSD 4.x and "rndc-confgen -a" just sits there. + </para> + </question> + <answer> + <para> + /dev/random is not configured. Use rndcontrol(8) to tell + the kernel to use certain interrupts as a source of random + events. You can make this permanent by setting rand_irqs + in /etc/rc.conf. + </para> + <informalexample> + <programlisting> +/etc/rc.conf +rand_irqs="3 14 15"</programlisting> + </informalexample> + <para> + See also + <ulink url="http://people.freebsd.org/~dougb/randomness.html"> + <http://people.freebsd.org/~dougb/randomness.html></ulink>. + </para> + </answer> + </qandaentry> + + </qandadiv> <!-- FreeBSD --> + + <qandadiv><title>Solaris</title> + + <qandaentry> + <question> + <para> + How do I integrate BIND 9 and Solaris SMF + </para> + </question> + <answer> + <para> + Sun has a blog entry describing how to do this. + </para> + <para> + <ulink + url="http://blogs.sun.com/roller/page/anay/Weblog?catname=%2FSolaris"> + <http://blogs.sun.com/roller/page/anay/Weblog?catname=%2FSolaris> + </ulink> + </para> + </answer> + </qandaentry> + + </qandadiv> + + <qandadiv><title>Apple Mac OS X</title> + + <qandaentry> + <question> + <para> + How do I run BIND 9 on Apple Mac OS X? + </para> + </question> + <answer> + <para> + If you run Tiger(Mac OS 10.4) or later then this is all you need to do: + </para> + <informalexample> + <programlisting> +% sudo rndc-confgen > /etc/rndc.conf</programlisting> + </informalexample> + <para> + Copy the key statement from /etc/rndc.conf into /etc/rndc.key, e.g.: + </para> + <informalexample> + <programlisting> +key "rndc-key" { + algorithm hmac-md5; + secret "uvceheVuqf17ZwIcTydddw=="; +};</programlisting> + </informalexample> + <para> + Then start the relevant service: + </para> + <informalexample> + <programlisting> +% sudo service org.isc.named start</programlisting> + </informalexample> + <para> + This is persistent upon a reboot, so you will have to do it only once. + </para> + </answer> + + <answer> + <para> + Alternatively you can just generate /etc/rndc.key by running: + </para> + <informalexample> + <programlisting> +% sudo rndc-confgen -a</programlisting> + </informalexample> + <para> + Then start the relevant service: + </para> + <informalexample> + <programlisting> +% sudo service org.isc.named start</programlisting> + </informalexample> + <para> + Named will look for /etc/rndc.key when it starts if it + doesn't have a controls section or the existing controls are + missing keys sub-clauses. This is persistent upon a + reboot, so you will have to do it only once. + </para> + </answer> + </qandaentry> + + </qandadiv> + + </qandadiv> <!-- Operating-System Specific Questions --> + + </qandaset> +</article> |