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Old 12-11-2004, 02:40 PM   #1
Registered: Apr 2004
Location: Nowhere, Oblivion
Distribution: Ubuntu
Posts: 48

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Working with SMTP and Postfix

I am trying to open port 25 for postfix, or otherwise figure out what's going on.

nmap localhost

returns the following

25/tcp open smtp
80/tcp open http

nmap and .1 and


80/tcp open http

It seems that somewhere along the line something is blocking port 25. I am wondering what it could be? My ISP isn't blocking port 25 (Shouldn't be a concern anyway) but I can't determine what the heck is causing it. I've looked at the router and looked at the IP tables/firewall and everything there seems fine (I'm new at this, so I may be reading it wrong).

Am I missing something? Do you need more information to help me solve the problem?

I'm running Ubuntu/Debian.
Old 12-12-2004, 05:20 PM   #2
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Registered: Mar 2004
Location: Wales, UK
Distribution: Debian, Ubuntu
Posts: 1,075

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The default config of SMTP servers to only listen to localhost. The reason is that SMTP is used by internal services to send information by e-mail to the administrator, and on most Linux systems it shouldn't be relaying messages from other machines.

If you look in /etc/aliases you will see that lots of accounts are aliased to 'root', and at bottom there is a note to alias root itself to the e-mail address of the administrator. When you've done that, run 'newaliases' for the change to take effect. You'll then start getting messages through to your account from various automated processes.

To enable your system to act as the mail server for a domain you'll need to edit /etc/postfix/ It's fairly well commented, and the documentation on is helpful as well, from what I remember.

Hope that helps.


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