Sendmail not accepting connections on port 25

[Robert Bonomi]

> Date: Tue, 19 Jul 2011 00:03:58 -0700
> From: ssgriffonuser <ssgriffonuser at gmail.com>
> Subject: Sendmail not accepting connections on port 25
>
> Hi all,
>
> I'm having difficulty getting sendmail set up on my server.  I can send 
> and receive to localhost and I can send to external networks but I can 
> not receive from external networks (I receive a 550: Address rejected).  

What does the sendmail LOG FILE show?

> Netstat says sendmail is listening on port 25 but I cannot telnet to it.

Netstat just says "something" has port 25 open on 'any' address -- this may,
or may *not* be the sendmail instance you think is running.  It probably 
*IS*, but you need to be sure.

> When I do a port scan of the server, nmap does not show anything on port 
> 25 but does show smtp on 587.

May I recommend 'lsof'?

The command-line  "lsof -n -P |grep IPv"  will show exactly what processes
have have what ports, on what addresses, open.

>
> As far as configuration goes, I added my hostname to 
> /etc/mail/local-host-names and created a /etc/host/virtusertable that 
> looks like:
>
> admin at host.com    shane
> shane at host.com    shane
>
> then I ran 'make all install restart' .

*Unless* you modified the .mc  file, I believe 'virtusertable' should be in
/etc/mail, not /etc/host.

what does 'grep Kvirtuser /etc/mail/sendmail.cf' show?

Lastly, you need to run 'makemap hash virtusertable' in the directory where
the virtusertable file lives.