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Re: [suse-security] Opening SMTP for Postfix

Quoting Eric Kahklen <eric@xxxxxxxxxxx>:
> I just installed SuSE 9.0 with Postfix and am trying to test
> connectivity by telneting to port 25 and get a connection refused.
> Scanning the box with NMAP shows port 25 closed.  If I telnet to
> localhost on port 25 from the box I connect with the mail system
> prompt.  I tried running the firewall tool in yast2 to allow SMTP but
> still no luck.  Does anyone know where to check to see where I can open
> this port?

lsof is your friend.  Run 'lsof | grep LISTEN' as root, and you'll see something

sshd     1246  root    5u  IPv6 2859  TCP *:ssh (LISTEN)
master   1760  root   11u  IPv4 4292  TCP localhost:smtp (LISTEN)

You'll notice that sshd is listening for any address, but master (postfix's
process) is only listening to localhost.  Thus, regardless of the firewall
settings, postfix won't listen to anyone coming from outside.

Others have pointed out where to fix this in postfix's configuration, but I
thought I'd chime in on how you can tell where the problem is, in case you run
into this type of thing in the future.

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