Identifying open ports (was: enable DNS)

[Kenneth Porter]

--On Monday, June 14, 2004 12:06 PM -0600 "Rodolfo J. Paiz" 
<rpaiz at simpaticus.com> wrote:

> If you do something like "netstat -leanp | grep 80" you should see
> whether Apache is listening on that port or not. However, the firewall
> may still be blocking that port; check your iptables configuration to
> make sure.

I usually use "lsof -i -n" (list open files, IP ports only, numeric (no DNS 
lookups)), but one must be root to use this. As with netstat, pipe the 
result through grep to identify specific ports.