How to Activate the SMTP-Authentication on Other Mail Servers (Postfix)

Support knowledgebase (rsimai_slox_smtp_auth)
Applies to

Openexchangeserver: Version 4

Situation

You want to activate SMTP-AUTH to allow the authentication of Openexchange Server as client on another mail server.
This description focuses on the Openexchange Server, but it should also work with the standard distribution in the cases where Postfix is used as an MTA.
A description for Sendmail is available in the article "SMTP-AUTH Client with Sendmail" (http://sdb.suse.de/en/sdb/html/sendmail_smtp_auth.html)

Why SMTP-AUTH

Many providers only accept e-mail messages via SMTP from clients that have previously authenticated on the server. The reason is that dial-in connections make it very difficult to control who has sent what to whom. The increasing presence of SPAM makes it necessary to verify whether the user is authorized or not. 'pop before smtp' is often used for this purpose. It works by enabling the sender to use the provider's SMTP server during a given period of time only after an (authenticated) POP retrieval. The problem arises mostly when your mail server is only temporarily connected to the Internet, i.e. without a dedicated line or a static IP address.

Requirement

Postfix has been installed and configured on your system. Your ISP has provided you with an access login and password that can be used for the SMTP authentication on the server. Attention: This is not a matter of course. Please ask your ISP if you are able to use SMTP-AUTH.

Procedure

  1. Make sure that the following entries are available in /etc/postfix/main.cf or insert them if necessary:
    smtp_sasl_auth_enable = yes
    smtp_sasl_security_options = noanonymous
    smtp_sasl_password_maps = hash:/etc/postfix/saslpasswd
    

    Check your spelling: 'smtp' and 'smtpd' are not the same!

  2. Create the file /etc/postfix/saslpasswd with the following content:
    destination.host.de      username:password
    
    destination.host.de is usually the relay host you use. With these entries, you instruct Postfix to deliver via SMTP-AUTH all the messages transmitted through the defined host whenever possible. Other transport routes will be handled as hitherto.

  3. Finally, generate the new map and reload the configuration:
    postmap /etc/postfix/saslpasswd
    rcpostfix reload
    			

Potential Problems


Keywords: OPENEXCHANGE SERVER, SLOX, POSTFIX, SMTP, AUTH, SASL

Categories: SuSE Linux IMAP Server

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SDB-rsimai_slox_smtp_auth, Copyright SuSE Linux AG, Nürnberg, Germany - Version: 06. Dec 2002
SuSE Linux AG - Last generated: 06. Dec 2002 by ip (sdb_gen 1.40.0)