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Re: [TCLUG:19428] identifying the program listening at a port



> > nmap is showing me a couple of odd ports open on one of my boxes.  These
> > ports are not listed in /etc/services and I don't seem to have anything
> > unexpected in my process table...
> 
> I'd bet they're your NIS/NFS/blah stuff..

> > Anyone know of a program that will identify which app/pid/whatever is
> > listening at a specified port?
> 
> I usually use something like this:
> 
>   lsof | grep IPv4
> 
> which gives a pretty good list of what is open..

lsof -i will do it in one command. Note that this still won't show ports
the kernel is using, namely kernel nfsd. Which seems to insist on
running random unprivleged ports, making it a pain to firewall out. It
seems to start out on 1024, but if you restart the NFS server it seems
to start picking other ports... Argh.