[CLUE-Tech] how to troubleshoot smtp server

[Jeffrey Greer]

Thanks Jim.  That was it.  :)  I think I need to rtfm a little less.  Thanks 
to everyone for the quick replies.

On Tuesday 05 February 2002 11:06 am, you wrote:
> Jeffrey:
>
> This could be a firewall issue as Ed suggests, but given my experience with
> Red Hat 7.2 you could be up against an "off-by-default" situation that Red
> Hat set up.
>
> The default sendmail configuration for Red Hat 7.2 is to listen only on the
> IP address 127.0.0.1 and port 25.  This will cause other systems on the
> network to be unable to connect to sendmail on your box, even though
> sendmail is running fine and you can connect to it on localhost.
>
> If you run the following command "netstat -an | grep LIST | grep ^tcp" you
> will see all of the TCP listeners on your system.  You should see something
> like this:
>
> [3] danja.int.ca.pason.com:/home/ockers > netstat -an | grep LIST | grep
> ^tcp tcp        0      0 0.0.0.0:6000            0.0.0.0:*              
> LISTEN tcp        0      0 0.0.0.0:25              0.0.0.0:*              
> LISTEN tcp        0      0 0.0.0.0:22              0.0.0.0:*              
> LISTEN tcp        0      0 0.0.0.0:139             0.0.0.0:*              
> LISTEN tcp        0      0 0.0.0.0:515             0.0.0.0:*              
> LISTEN tcp        0      0 0.0.0.0:110             0.0.0.0:*              
> LISTEN tcp        0      0 0.0.0.0:23              0.0.0.0:*              
> LISTEN tcp        0      0 0.0.0.0:21              0.0.0.0:*              
> LISTEN tcp        0      0 0.0.0.0:989             0.0.0.0:*              
> LISTEN tcp        0      0 0.0.0.0:1024            0.0.0.0:*              
> LISTEN tcp        0      0 0.0.0.0:111             0.0.0.0:*              
> LISTEN
>
> Notice how on my system I am listening on the address 0.0.0.0 and port 25.
> This means that my system is accepting connections on all network
> interfaces for port 25 (sendmail).
>
> On your system, I am betting that the listener is "127.0.0.1:25" and that
> you do not have sendmail bound to any other interfaces.  You can verify
> this by running the netstat command.
>
> The way to fix this is in the /etc/sendmail.cf or in the
> /etc/mail/sendmail.mc. Here is the sendmail.mc information:
>
> dnl This changes sendmail to only listen on the loopback device 127.0.0.1
> dnl and not on any other network devices. Comment this out if you want
> dnl to accept email over the network.
> dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')
>
> The daemon_options above are commented out.  Yours are probably not
> commented out.  If you comment it out, then run "make" in the /etc/mail
> directory, then restart sendmail, your problem should go away.
>
> Hope this helps.
>
> --JimO
>
rewall rules.

-- 
Jeffrey Greer