External SMTP port not responding

[devostyle]

Hey Guys,
I have a Linux box running RH7.3 hosting my own domain. I am trying to configure the server to accept mail from external sources, but the smtp port does not respond. I can telnet to the smtp port(25) locally from a terminal session on the server and get the correct response from sendmail, but when I try it from an external machine I get an error saying the server actively refused the connection. Also when I do a port scan of the server, there is no response from the smtp port(25). I even went as far as to install a newer version of sendmail, but I get the same response. Does anyone have any suggestions?

Thanks in advance

devo

 

[hsravidatta]

Hi,
External machine in the sense. is it out of your LAN or internal LAN. Check the IPs relayaing. Does it relays on your N/W ???

regards,
Ravidatta

 

[Morsing]

Hi,
I think your firewall is blocking the port or sendmail isn't listening on that interface.

Do you run your own firewall?? Try 'ipchains -L input'.

Cheers Henrik Morsing
IBM Certified AIX 4.3 Systems Administration

 

[devostyle]

I mean external as in a separate machine within my network and I am not running ipchains. Some how, sendmail is only listening on the local port. I say this because if I open a terminal on the server and telnet to localhost at port 25, I get the response that sendmail is supposed to give. But if I do the same on another computer on my network, I get nothing.

 

[RhythmAce]

send mail doesn't listen to the eth0 device by default on some distros. For security it is set to just look at the loopback device on 172.0.0.1. Look for a line in /etc/mail/sendmail.mc that looks like this:

DAEMON_OPTIONS(`port=smtp, Addr=172.0.0.1, Name=MTA')

What you need to do is comment it out by putting "dnl" in front of it or change the loopback ip to your eth0 ip. Then create a new sendmail.cf with the following command:

m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf

restart sendmail and you're all set.

 

[devostyle]

RhythmAce, You are the freakin man!!! It worked like a charm. I have been banging my head over this for a week. Thanks for you help man.

devo