This is part of The Pile, a partial archive of some open source mailing lists and newsgroups.
Subject: Re: How to check what ports are being used?? From: a mole <mole@pasdex.com.au> Date: Sat, 18 Dec 1999 14:36:10 +1000 (EST) On Fri, 17 Dec 1999, Steve <sgulick@poboxes.com> wrote: > Is there a command that will list the ports that are being used and > what is it? > Or is this a stuuuupppid question and I'm just having a very bad day? the highly excelent program lsof tells you what you want to know. Running 'lsof -i' will tell you all the networking ports open and the command, pids, users names ect associated with the port. I'm pretty sure lsof is standard issue on redhat these days... === Subject: Re: How to check what ports are being used?? From: "Greg W" <redhat_list@mail.com> Date: Sat, 18 Dec 1999 16:52:04 +1100 I was looking forward to trying lsof -i but none of my boxes have it.....what provides this... however, maybe one of these combinations will help Steve.... netstat netstat -an or to refresh watch netstat watch netstat -an === Subject: Re: How to check what ports are being used?? From: "Arni Raghu" <arni@caip.rutgers.edu> Date: Sat, 18 Dec 1999 01:52:13 -0500 did not come with my redhat... Just download it from freshmeat...very useful and great program.. === Subject: Re: How to check what ports are being used?? From: Alan Mead <adm@ipat.com> Date: Fri, 17 Dec 1999 17:26:16 -0600 At 04:37 PM 12/17/99 -0500, Steve wrote: >Is there a command that will list the ports that are being used and what is it? > >Or is this a stuuuupppid question and I'm just having a very bad day? The file /etc/services lists the services that are supposed to be running. So if someone tries to connect to port 110, look in /etc/services to see what service usually answers that request. But be aware that some (many? all?) services do things like negotiate other ports (e.g., ftp) so port 10182 could be busy with an ftp or telnet session. 'netstat' will tell you about "open" connections but not about other ports. There is a package called ntop that does a better job of what you want to do. And there are others. === Subject: Re: How to check what ports are being used?? From: linuxlists@whatever.net Date: Fri, 17 Dec 1999 02:54:50 -0800 (PST) On Fri, 17 Dec 1999, Steve wrote: > Is there a command that will list the ports that are being used and > what is it? Is this what you're looking for? cat /proc/net/tcp cat /proc/net/udp and cat /proc/net/unix just for good measure It might be nice to have a perl script to turn the tcp and udp stuff into a more readable format. It took a minute to figure out that them big hex numbers were my ip addresses in reverse. :-) /proc/net/ip_masq/* might be worth a look too if you're doing any masquerade stuff. I'm not, so the files therein aren't very interesting! === Subject: Re: How to check what ports are being used?? From: JWalsh <jwalsh@adsl-78-160-122.gnv.bellsouth.net> Date: Sat, 18 Dec 1999 15:16:01 -0500 (EST) > The file /etc/services lists the services that are supposed to be running. > So if someone tries to connect to port 110, look in /etc/services to see > what service usually answers that request. But be aware that some (many? > all?) services do things like negotiate other ports (e.g., ftp) so port > 10182 could be busy with an ftp or telnet session. This file specifies well known ports which the services listed use. It does not indicate what services are supposed to be running. And it isn't necessarily accurate if the administrator chooses to specify a different port for a given service. J. ===