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How to solve SMTP-AUTH errors on Postfix (or any other mailserver) behind a Cisco PIX firewall
Fri, 20/11/2009 - 23:36 — TomàsYou have configured authentication on outgoing mail (SMTP-AUTH) on your mailserver (postfix, in this case) and it works great. But when you put it on production, the users complain because they can't send emails.
What do you do? You try to follow the communication step by step. That is, you telnet to port 25 and follow step by step the authentication. The conversation goes like this (the lines beginning with "->" are written by me, without the "->" part):
tomas@client:~$ telnet smtp.example.com 25
Trying 1.2.3.4...
Connected to smtp.example.com.
Escape character is '^]'.
220 smtp.example.com ESMTP server ready
-> EHLO example.com
250-smtp.example.com
250 AUTH CRAM-MD5 DIGEST-MD5
-> AUTH FOOBAR
504 Unrecognized authentication type.
-> AUTH CRAM-MD5
334 PENCeUxFREJoU0NnbmhNWitOMjNGNndAZWx3b29kLmlubm9zb2Z0LmNvbT4=
-> ZnJlZCA5ZTk1YWVlMDljNDBhZjJiODRhMGMyYjNiYmFlNzg2ZQ==
235 Authentication successful.
If you take anything from here, and it is useful for you, buy me a beer! (I pay second round)
