Setting up SMTP-AUTH for SENDMAIL or POSTFIX

Support knowledgebase (fhassel_smtp_auth)
Applies to

SuSE Linux: Versions since 8.0

Situation

Your mail provider uses the authentication method SMTP-AUTH on its SMTP servers for sending e-mail. You send your e-mail with Sendmail or Postfix and want to activate SMTP-AUTH.

Procedure

Sendmail as MTA

If you use Sendmail (standard up to SuSE Linux 8.0) as your MTA (Mail Transfer Agent), edit the variable SMTP_AUTH_MECHANISMS in the file /etc/sysconfig/sendmail with an editor of your choice. This variable must contain the authentication method. Most providers support PLAIN and LOGIN, although user data are transmitted in plain text through these methods. CRAM-MD5, on the other hand, is also a common mechanism, but it supports the encrypted transfer of user data. Ask your provider about the supported methods or find it by connecting with telnet to port 25 on the SMTP server:

linux:~ # telnet smtpserver.provider.com 25
Trying ...
Connected to smtpserver.provider.com.
Escape character is '^]'.

EHLO my.address.com

250-AUTH=LOGIN CRAM-MD5 PLAIN
250-AUTH LOGIN CRAM-MD5 PLAIN
This mail server supports the mechanisms LOGIN, CRAM-MD5, and PLAIN.

Then edit the file /etc/mail/auth/auth-info by simply inserting the following:

AuthInfo:smtpserver.provider.com "U:username" "P:password"
'smtpserver.provider.com' must be replaced with the provider's SMTP server, 'username' with the user name, and 'password' with the password. Finally, execute the following commands in a root shell to make changes apply.
SuSEconfig --module sendmail
rcsendmail restart

Postfix as MTA

If you use Postfix as your MTA (standard from SuSE Linux 8.1 on), refer to the article "How to Activate the SMTP-Authentication on Other Mail Servers (Postfix)" (http://sdb.suse.de/en/sdb/html/rsimai_slox_smtp_auth.html) for instructions.
See also:
o Configuring E-Mail with YaST2
o How to Activate the SMTP-Authentication on Other Mail Servers (Postfix)
o SMTP-AUTH Client with Sendmail

Keywords: SMTP-AUTH, MTA, SENDMAIL, POSTFIX, LOGIN, PLAIN, CRAM-MD5, AUTHENTICATION

Categories: Email

SDB-fhassel_smtp_auth, Copyright SuSE Linux AG, Nürnberg, Germany - Version: 03. Mar 2003
SuSE Linux AG - Last generated: 25. Jun 2003 by afaber (sdb_gen 1.40.0)