telnet to port 25

Unanswered Question
Nov 26th, 2008
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Through our ASA we can telnet to a email server but get 500 5.5.1 Command unrecognized: "XXXX" when we try to use the commands. Any help would be appreciated.


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sachinraja Wed, 11/26/2008 - 11:30
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Hello spencer

You might really not have the right access for it.. ASA works on layer 3/4 and allows a packet on port 25. but as it hits the server , your communication is on layer 7 and the application decides what you have to do ! So, this is more to do with Application. If you can telnet to port 25 and till you arent timed out, I do not see this as a network issue

Hope this helps..


cisco24x7 Wed, 11/26/2008 - 11:35
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"no fixup protocol smtp 25" and your mail will

work. It is a known issue with ASA/Pix and



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