Sendmail doesn't listen to other addresses than 127.0.0.1

[ATC]

Sendmail is running and can be reached using "telnet localhost 25" but does not accept connections from any other hosts.

[ATC]

First of all, rule out the possibility of firewalls blocking access. This is the most common cause for problems.

Then check your "/etc/hosts.allow" and "/etc/hosts.deny" files. Under normal circumstances you'll want anyone to be able to access sendmail.

Finally, verify that the file "/etc/mail/sendmail.mc" contains a line "Djdomain.com" where "domain.com" is replaced with the official domain name of your mail server.