redhat 9: sendmail port 25 not allowing outside telnet

aagha · 08-20-2003, 10:11 AM

I have a baffling problem...I can not get sendmail to communicate on port 25 from the outside.

I can "telnet localhost 25" and talk to sendmail, no problem.

But I CAN'T "telnet <my server IP> 25" which is the address of the
machine on my NAT...I have turned off firewalls, and can access
port 23, 22 etc...from outside by not 25....

Any ideas? I've configured the /etc/mail/access and
/etc/mail/local-host-names correctly, is there something new in redhat 9 that I'm missing?

LinuxRacr · 08-20-2003, 10:31 AM

This is probably a good thing for securty's sake...

enigmaweb · 08-20-2003, 10:49 AM

What ISP are you using? I would bet that you may been in the same situation I'm in. A lot of broadband ISP's are blocking Port 25 in order to prevent spam relays from originating from their servers. If this is the case, you're not going to be able to access Port 25 from the outside world. For more info on how to get around this (if this is the case), please see my ongoing POP3 Is Killing Me Topic.

If you don't have Port 25 blocked, you might want to check any firewalls or routers you have in front of your server to ensure that they are allowing the telnet port and SMTP port through.

Looking_Lost · 08-20-2003, 12:28 PM

Have you configured sendmail to listen on your real ip rather than the default 127.0.0.1?

joseph · 08-28-2003, 11:23 PM

edit your sendmail.cf, find the ip: 127.0.0.1 and change it to 0.0.0.0 (don't touch anything else

, cause u can

)
save your configuration and restart your sendmail (service sendmail restart).
because 127.0.0.1 will ask sendmail to listen local interfaces rather than other interface, but 0.0.0.0 will ask sendmail to listen all interfaces.

Is it solve your problem