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RE: [Sheflug] Postfix setup



On Mon, 2003-08-04 at 16:28, Chris Johnson wrote:
> >
> > Don't worry about not be able to connect on port 23 -  it's a
> > telnet port -
> > usually off for a security reasons. sshd is much better option if you
> > need remote login.
> 
> Tried telnetting on both 23 and 25 no luck.  That would at least prove the
> networking was working as far as the application leayer (guess whose just
> been on a cisco course!)

Does it?

When you hit telnet <IP> 23 your client side works down the OSI model
(Application->Physical) and then works up (Physical->Application) on the
server. So if you can't telnet port 23 or port 25 all that proves is
that somewhere there's a problem somewhere between the Application layer
on the client and server. 

The cause of not been able to telnet ports 23 and 25 could be the
physical layer modifying random bits as they travel across the wire.
(however it would be a very weird sense of random- for it to not cause
checksums on data-link/tcp packets to become invalid)

However the physical layer could be clean, and it could be that
client/server are doing something weird within the IP packet (something
like IP header compression can mess up if one side has no notion that
it's possible to compress headers).

I'd guess first at postifx not running (try restarting while looking at
wherever SuSE keeps it's log (tail -f /var/log/messages on RH)- there
might be useful clues that appear. I'd expect you to be able to telnet
port 25 on the box on loopback/interface IP if postfix is running.

If you manage to telnet to postfix on the box then can't from an
seperate box look at the firewall.

BTW: can't remember if you mentioned re-installing SuSE- that's a bit
too much (checking if SuSE is rpm based, long time since I used it).
rpm -q --list postfix (to list files, pay attention to config files).
rpm -e postfix (to remove postfix), check the config files have gone
then rpm -ivh postfix*.rpm. 

BTW2: SuSE/RedHat have just released security fixes for postfix  


-- 
Regards,
Adam Allen.

adam@dynamicinteraction.co.uk
pgp http://search.keyserver.net:11371/pks/lookup?op=vindex&search=adam%40dynamicinteraction.co.uk

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