Faximum TechNote #236

Faximum TechNote #236

(http://www.faximum.com/technotes/236)

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TITLE:    #236 - Configuring Sendmail on Red Hat 7.2

KEYWORDS: sendmail red hat redhat rhs 

RELEASE:  Faximum Messaging Server 2

CLASSIFICATION: Any-FMS

PROBLEM:  During pre-installation testing it has been determined that
	  the Red Hat 7.2 system is not configured to accept email from
	  external systems. This is feature is needed if the RHS system
	  is going to be used to accept email from other systems to be
	  delivered by fax.

	  There are several areas that need to be checked to ensure that
	  your system can accept external email. This technote outlines
	  steps to check and reconfigure your email server.

SOLUTION:	  
	0) To test to see if a server is accepting external email
	   please run telnet from another system on the same
	   network.

	   For example, if the IP address for the server in question
	   is 1.2.3.4 then you can test by running the following
	   command:

	   	telnet 1.2.3.4 25
	
	   (This will work on Linux, UNIX, Windows, and Mac OS X.)

	   If the server is accepting email then you will see a line
	   that starts with "220" and contains the letters "SMTP".
	   Type QUIT to exit.

	   If the server is not accepting email then you will receive
	   an error message from telnet.


	1) Check that sendmail or postfix has been installed on your
	   system by running:
	
		rpm -q sendmail
	   and
	   	rpm -q postfix

	   If sendmail is installed you will see a response similar to:

	   	sendmail-8.11.6-3

	   If postfix is installed you will see a response similar to:

	   	postfix-20010228-1

	   If neither mail server is installed on your system (if you 
	   get a response similar to "package xxxx is not installed")
	   then please consult your documentation to determine how
	   to install the sendmail package.

	   If you have postfix then please contact Faximum Technical
	   Support (support@faximum.com) for guidance (this Technote
	   only applies to sendmail on Red Hat 7.2).


	2) Check to see if sendmail is listening on the SMTP port 25.
	   Run the following:

	   	 netstat -an | grep :25
	
	   If you get no output then sendmail is not running and you need
	   to address that problem before proceeding further.

	   If you see a line similar to the following:

		   tcp   0   0 0.0.0.0:25     0.0.0.0:*       LISTEN

	   then sendmail is properly configured and you can proceed to
	   step xx below.

	   If you see a line similar to the following:

		   tcp   0   0 127.0.0.1:25     0.0.0.0:*       LISTEN

	   then sendmail has been configured to ignore outside connections.
	   Please proceed to step 3.


	3) If sendmail is configured to listen only on 127.0.0.1 then
	   please edit the sendmail.cf file (usually found in /etc)
	   and look for a line of the form:

		O DaemonPortOptions=Port=smtp,Addr=127.0.0.1, Name=MTA

	   and comment it out by putting a # in the first column:

		# O DaemonPortOptions=Port=smtp,Addr=127.0.0.1, Name=MTA


	   Then restart sendmail by running:

		/etc/rc.d/init.d/sendmail restart

	   After doing this repeat the test in step #2 to verify that
	   sendmail is now listening on 0.0.0.0


	4) Look at the contents of the file /etc/sysonfig/ipchains
	   for a line like:

		-A input -s 0/0 -d 0/0 25 -p tcp -y -j ACCEPT

	   If the file does not contain such a line then add it
	   as the first of the lines that start with a "-A".

	   After editing the file then run:

		/etc/rc.d/init.d/ipchains restart

	
	5) At this point try running the test in step 0 (above) again
	   to verify that your system is now accepting external email
	   requests. If it is not, please contact Faximum Technical
	   Support (support@faximum.com) for further assistance.


TechNote: 236 - Copyright 2002 Faximum Software Inc., All Rights Reserved.
Last Updated: Wed Mar  6 00:28:02 PST 2002
Find all Faximum TechNotes at http://www.faximum.com/support

Copyright 2001 Faximum Software Inc. All Rights Reserved.