Sendmail - Revision history

Sstrutt: /* Troubleshooting */ Added "Process Queue"

2015-07-28T10:14:06Z

Troubleshooting: Added "Process Queue"

← Older revision		Revision as of 10:14, 28 July 2015
Line 55:		Line 55:

	== Troubleshooting ==		== Troubleshooting ==
			=== Process Queue ===
			sendmail -v -q

			Performs a queue process run

	=== Queue Size ===		=== Queue Size ===
	sendmail -bp		sendmail -bp

Sstrutt: /* Troubleshooting */ Added "Find Email To/From Email/IP Address"

2014-02-06T10:46:40Z

Troubleshooting: Added "Find Email To/From Email/IP Address"

@@ Line 84: / Line 84: @@
 Some text for the email
+.
 </pre>
 [[Category:Linux]]
 [[Category:Applications]]

Sstrutt: /* Configuration */ Added "Allowed/Denied Senders/Receivers"

2013-11-19T10:45:04Z

Configuration: Added "Allowed/Denied Senders/Receivers"

← Older revision		Revision as of 10:45, 19 November 2013
Line 35:		Line 35:

	Taken from the recommendations at http://www.trilug.org/~jonc/mailserver/PartIII.html		Taken from the recommendations at http://www.trilug.org/~jonc/mailserver/PartIII.html

			=== Allowed/Denied Senders/Receivers ===
			First check that the feature is enabled in <code>sendmail.mc</code>, look in (don't worry about a <code>dnl</code> at the end of the lines, only if they're at the front)
			FEATURE(access_db)
			FEATURE(blacklist_recipients)

			You can then edit the <code>access</code> to allow or deny email, eg
			<pre>
			# Allow connections from (relaying) from the following...
			Connect:localhost.localdomain RELAY
			Connect:localhost RELAY
			Connect:127.0.0.1 RELAY
			Connect:192.168.10 RELAY

			# Deny email destined for recipients
			server.domain.com 550 Mail relay disabled for this recipient
			user@another.com 550 Mail relay disabled for this recipient
			</pre>

	== Troubleshooting ==		== Troubleshooting ==

Sstrutt: Initial creation

2013-11-13T15:04:36Z

Initial creation

New page

Sendmail is an old [[Acronyms#S|SMTP]] server application. Those in the know generally seem to prefer either [http://www.exim.org/ Exim] or [http://www.postfix.org/ Postfix], but sendmail is still included by default in many Linux distributions, so you tend you end up using sendmail by default. Whilst sendmail is highly configurable, its not the easiest to configure.

== Configuration ==
=== Relay ===
By default, sendmail will send emails direct to the receiving [[Acronyms#M|MTA]]/email server. However, you can force it to send via another server (a mime server for example).

Edit the config file - <code>/etc/mail/sendmail.cf</code>, and add IP or name of the SMTP server you want to send to...
# "Smart" relay host (may be null)
DS[10.0.226.60]

If you need/want to use a hostname...
# "Smart" relay host (may be null)
DSsmtp.domain.com

Restart the service, '''and test'''
service sendmail restart

=== Time-Outs ===
Out of the box, sendmail allows for some generous time-outs. It really wants to deliver mail on the first attempt. However, you may prefer to deliver what you can quickly, and leave mail destined for slower receivers to be delivered later. For example if you need to handle bursts of messages, and where the sending system(s) need(s) to be freed up as soon as possible.

Edit the config file - <code>/etc/mail/sendmail.cf</code>,
<pre>
# timeouts (many of these)
...
O Timeout.iconnect=5s
...
O Timeout.mail=5m
...
O Timeout.datainit=2m
</pre>

Restart the service, '''and test'''
service sendmail restart

Taken from the recommendations at http://www.trilug.org/~jonc/mailserver/PartIII.html

== Troubleshooting ==
=== Queue Size ===
sendmail -bp

or if sendmail's queued emails are residing in <code>/var/spool/mqueue</code>...
find /var/spool/mqueue -type f -name qf\* -print|wc -l|tr -d ' '

=== Send Test Email ===
==== From Local Server ====
From the local server, you test by creating a text file with the email contents (eg <code>/tmp/testmail</code>)..
To: you@domain.com
Subject: Test email via sendmail
From: your-server

Some content

...and then send using...
sendmail -vt < /tmp/testmail

==== From Remote Server ====
You can use telnet, but not from a Windows server (it just doesn't seem to work, use [http://www.blat.net/ blat] instead). Replace the IP address with that of your server...
<pre>
telnet 192.168.10.11 25
HELO domain.com
MAIL FROM:your-server
RCPT TO:you@domain.com
DATA
Subject: Test email via sendmail
Some text for the email
.
</pre>

[[Category:Linux]]
[[Category:Applications]]