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| author | Rainer Gerhards <rgerhards@adiscon.com> | 2008-04-10 08:06:48 +0200 |
|---|---|---|
| committer | Rainer Gerhards <rgerhards@adiscon.com> | 2008-04-10 08:06:48 +0200 |
| commit | 9584c81df387adcdcd7b84078eda48092049101d (patch) | |
| tree | c4a6f8f5763391925af02fb703525a7f6b9d0695 /doc | |
| parent | 0f3dbecb867bc8ed852389ae9642be5d0f3636aa (diff) | |
| download | rsyslog-9584c81df387adcdcd7b84078eda48092049101d.tar.gz rsyslog-9584c81df387adcdcd7b84078eda48092049101d.tar.xz rsyslog-9584c81df387adcdcd7b84078eda48092049101d.zip | |
added ommail.html - I forgot to add this file...
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/ommail.html | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/doc/ommail.html b/doc/ommail.html new file mode 100644 index 00000000..b6b7c2ad --- /dev/null +++ b/doc/ommail.html @@ -0,0 +1,128 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<html><head><title>mail output module - sending syslog messages via mail</title> + +</head> +<body> +<h1>Mail Output Module (ommail)</h1> +<p><b>Module Name: ommail</b></p> +<p><b>Author: </b>Rainer Gerhards +<rgerhards@adiscon.com></p> +<p><b>Description</b>:</p> +<p>This module supports sending syslog messages via mail. Each +syslog message is sent via its own mail. Obviously, you will want to +apply rigorous filtering, otherwise your mailbox (and mail server) will +be heavily spammed. The ommail plugin is primarily meant for alerting +users. As such, it is assume that mails will only be sent in an +extremely limited number of cases.</p> +<p>Please note that ommail is especially well-suited to work in +tandem with <a href="imfile.html">imfile</a> to +watch files for the occurence of specific things to be alerted on. So +its scope is far broader than forwarding syslog messages to mail +recipients.</p> +Ommail uses two templates, one for the mail body and one for the +subject line. If neither is provided, a quite meaningless subject line +is used and the mail body will be a syslog message just as if it were +written to a file. It is expected that the users customizes both +messages. In an effort to support cell phones (including SMS gateways), +there is an option to turn off the body part at all. This is considered +to be useful to send a short alert to a pager-like device.<br> +<br> +It is highly recommended to use the "<span style="font-weight: bold;">$ActionExecOnlyOnceEveryInterval +<seconds></span>" directive to limit the amount of +mails that potentially be generated. With it, mails are sent at most in +a <seconds> interval. This may be your life safer. And +remember that an hour has 3,600 seconds, so if you would like to +receive mails at most once every two hours, include a +"$ActionExecOnlyOnceEveryInterval 7200" immediately before the ommail +action. Messages sent more frequently are simpy discarded.<span style="font-weight: bold;"></span> +<p><b>Configuration Directives</b>:</p> +<ul> +<li><span style="font-weight: bold;">$ActionMailSMTPServer</span><br> +Name or IP address of the SMTP server to be used. Must currently be +set. The default is 127.0.0.1, the SMTP server on the local machine. +Obviously it is not good to expect one to be present on each machine, +so this value should be specified.<br> +</li> +<li><span style="font-weight: bold;">$ActionMailSMTPPort</span><br> +Port number or name of the SMTP port to be used. The default is 25, the +standard SMTP port.</li> +<li><span style="font-weight: bold;">$ActionMailFrom</span><br> +The email address used as the senders address. There is no default.</li> +<li><span style="font-weight: bold;">$ActionMailTo</span><br> +The recipients email address. There is no default.</li> +<li><span style="font-weight: bold;">$ActionMailSubject</span><br> +The name of the <span style="font-weight: bold;">template</span> +to be used as the mail subject. If this is not specified, a more or +less meaningless mail subject is generated (we don't tell you the exact +text because that can change - if you want to have something specific, +configure it!).</li> +<li><span style="font-weight: bold;">$ActionMailEnableBody</span><br> +Setting this to "off" permits to exclude the actual message body. This +may be useful for pager-like devices or cell phone SMS messages. The +default is "on", which is appropriate for allmost all cases. Turn it +off only if you know exactly what you do!</li> +</ul> +<b>Caveats/Known Bugs:</b> +<p>The current ommail implementation supports <span style="font-weight: bold;">SMTP-direct mode</span> +only. In that mode, the plugin talks to the mail server via SMTP +protocol. No other process is involved. This mode offers best +reliability as it is not depending on any external entity except the +mail server. Mail server downtime is acceptable if the action is put +onto its own action queue, so that it may wait for the SMTP server to +come back online. However, the module implements only the bare SMTP +essentials. Most importantly, it does not provide any authentication +capabilities. So your mail server must be configured to accept incoming +mail from ommail without any authentication needs (this may be change +in the future as need arises, but you may also be referred to +sendmail-mode).</p> +<p>In theory, ommail should also offer a mode where it uses the +sendmail utility to send its mail (<span style="font-weight: bold;">sendmail-mode</span>). +This is somewhat less reliable (because we depend on an entity we do +not have close control over - sendmail). It also requires dramatically +more system ressources, as we need to load the external process (but +that should be no problem given the expected infrequent number of calls +into this plugin). The big advantage of sendmail mode is that it +supports all the bells and whistles of a full-blown SMTP implementation +and may even work for local delivery without a SMTP server being +present. Sendmail mode will be implemented as need arises. So if you +need it, please drop us a line (I nobody does, sendmail mode will +probably never be implemented).</p> +<p><b>Sample:</b></p> +<p>The following sample alerts the operator if the string "hard +disk fatal failure" is present inside a syslog message. The mail server +at mail.example.net is used and the subject shall be "disk problem on +<hostname>". Note how \r\n is included inside the body +text +to create line breaks. A message is sent at most once every 6 hours, +any other messages are silently discarded (or, to be precise, not being +forwarded - they are still being processed by the rest of the +configuration file).<br> +</p> +<textarea rows="15" cols="80">$ModLoad ommail +$ActionMailSMTPServer mail.example.net +$ActionMailFrom rsyslog@example.net +$ActionMailTo operator@example.net +$template mailSubject,"disk problem on %hostname%" +$template mailBody,"RSYSLOG Alert\r\nmsg='%msg%'" +$ActionMailSubject mailSubject +# make sure we receive a mail only once in six +# hours (21,600 seconds ;)) +$ActionExecOnlyOnceEveryInterval 21600 +# the if ... then ... mailBody mus be on one line! +if $msg contains 'hard disk fatal failure' then :ommail:;mailBody +</textarea><br> +<br> +A more advanced example plus a discussion on using the email feature +inside a reliable system can be found in Rainer's blogpost +"<a style="font-style: italic;" href="http://rgerhards.blogspot.com/2008/04/why-is-native-email-capability.html">Why +is native email capability an advantage for a syslogd?</a>" +<p>[<a href="rsyslog_conf.html">rsyslog.conf overview</a>] +[<a href="manual.html">manual index</a>] [<a href="http://www.rsyslog.com/">rsyslog site</a>]</p> +<p><font size="2">This documentation is part of the +<a href="http://www.rsyslog.com/">rsyslog</a> +project.<br> +Copyright © 2008 by <a href="http://www.gerhards.net/rainer">Rainer +Gerhards</a> and +<a href="http://www.adiscon.com/">Adiscon</a>. +Released under the GNU GPL version 3 or higher.</font></p> +</body></html>
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