How to find what's listening on what port

[Matthew Hawkins]

On Fri, 12 Oct 2001, Drake Diedrich wrote:
> On Fri, Oct 12, 2001 at 09:59:09AM +1000, Matthew Hawkins wrote:
> > Just a niggly... the answer isn't necessarily X.  6000 is an
> 
>    Yeah yeah, OK.  It *better* turn out to just be X ...

:)

I only mentioned this because I've seen so-called port hijackings, where
a service shutdown for maintenance refuses to restart because in the
mean time some other thing has "randomly" chosen its port to use as a
temporary data port.  All you know is the service cannot bind to its
port, so you first have to use lsof or whatever to work out what took
over, then go from there.

This is what happens when common services use unprivileged ports! :P

One common symptom is your X server refuses to start.  Another common
one is you can no longer view offsite web pages (proxy server refused to
start).  Goodbye also to development web servers, irc server, icq
client, etc...

-- 
Matt