Is it possible to find out what port(s) an application uses?

nikl · n00b Joined: 06 Feb 2003 Posts: 5 Location: Hamburg, DE

Hi there,

one thing I really liked about those windoze "desktop-firewalls" was the ability to setup a rule-set that made it possible to clearly define which ports a certain application was allowed to use or not. Unfortunately I haven't found such a possibility for linux yet. My iptables only watch ports - indepently from which application uses these ports. Netstat shows me which ports are effectively used. But unfortunately not which applications are using them.

Can anyone point me in the right direction? thanks in advance.
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carbon · Guru Joined: 27 Jun 2003 Posts: 455 Location: New York

if you dont need to know what port it uses in advance, you can use trafshow to monitor the traffic. it shows who is talking to you and who are you (all your process in your gentoo box) talking to on which port.
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uzik · Apprentice Joined: 17 Apr 2003 Posts: 257

I thought there was a command line option for netstat
to show the command line of the program using each port.
That tells you which program is using the port.

kashani · Posted: Thu Jul 31, 2003 6:37 pm Post subject:

netstat -ptln
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nikl · n00b Joined: 06 Feb 2003 Posts: 5 Location: Hamburg, DE

sschlueter · Posted: Thu Jul 31, 2003 7:15 pm Post subject:

credmp · Posted: Fri Aug 01, 2003 8:58 pm Post subject:

Hi,

just to add to the previous answers with netstat; you can also use lsof...