Find out which programs are listening TCP port
Answer:
Use the command: netstat -tlnp
# netstat -tlnp
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:443 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN


Where is the program listed? I don't think your answer answers the question...
@Mike
What distribution you are using?
If you are using Debian based, you can install netstats by
# sudo apt-get install net-tools