Re: Postfix listening on 25, unable to telnet to 25 - my first config

[Samy Ascha, Xel Media B.V.]

Hey,








Samy

On Nov 25, 2008, at 8:43 AM, Michael De Groote wrote:

Have you actually tried telnetting from other locations? I see you live in The netherlands, where it is common for ISPs to block this port to all destinations, other than their own SMTP servers. I think this is kind of fascist, but it does, somewhat, limit zombies from sending spam through regular channels. Whenever I need to do some manual SMTP'ing over a telnet connection, I first login to another host, somewhere in our public network, rather than doing it from my workstation/laptop. It sucks a bit, but I git used to it and just hope this helps preventing some SPAM being sent.

if you're connecting from a windoze machine, check the firewall (and antivirus, netsecurity, whatever crappy stuff) settings of the windoze machine. I've seen instances where outgoing connections to port 25 were being blocked by some Symantec product, or even the windoze firewall itself... (iirc)

Michael De Groote
ICT-coordinator Sint-Pietersschool Korbeek-Lo
ICT-support Sancta Maria Basisschool Leuven



You can see entries in the logfile called /var/log/messages

Regards,

Olivier

--
Olivier MJ Crepin-Leblond, Ph.D
Global Information Highway Ltd
http://www.gih.com/ocl.html
----- Original Message -----
From: D G Teed
To: Paul Cocker
Cc: postfix users list
Sent: Friday, November 21, 2008 2:47 AM



Paul Cocker schrieb:


Definitely nothing in between, of that I'm certain.

Are there any tools which will give me more information
about attempts
to connect to a port on a remote host?
use tcpdump for that purpose

please try

$ telnet $IP_OF_SMTP_HOST 25

and show exactly, what you get


I ran windump in the background and did a telnet to the IP, however a
findstr on the output file contains no matches. If I do the same thing
using the server name the only matching output in the dump is when the

by IP or name.

Am I doing something wrong?

There are a few things that can make postfix listen only locally.

One is firewall.  You say it isn't an issue.

On the postfix machine, if it is a Unix machine, use lsof -Pni to
verify what ports and addresses master is listening on.

If it is only listening to 127.0.0.1 then you have a problem with
inet_interfaces, or else the look up of the host name listed
in inet_interfaces.  On many Linux machines, the host
resolution order is hosts, dns, and so a bad entry
on /etc/hosts can sting you.

Make sure you don't have 127.0.0.1 set up with the internet host
name of the server in /etc/hosts.  It should be only localhost next to
127.0.0.1   I've seen Redhat installs with this messed up.

--Donald

On Fri, Nov 21, 2008 at 9:19 AM, Olivier MJ Crepin-Leblond <[EMAIL PROTECTED] > wrote: Also check SElinux if you are running this. It may prevent changes to the port config from taking place. Subject: Re: Postfix listening on 25, unable to telnet to 25 - my first config server performs a name lookup, after that there are no matching entries

PGP.sig
Description: This is a digitally signed message part