Using 'netstat -tulp' on my server box running under CentOS I have discovered strange listening ports 33363 (TCP) and 35661 (UDP). The thing is that 'PID/Program name' field for these ports contains nothing (dash actually). 'fuser -n tcp 33363' shows nothing. I have checked my box with chkrootkit and rkhunter utilities and it seems everything is O.K. Does anybody know what these sockets can be used for?
Have you tried with lsof?
lsof -i TCP:33363 lsof -i UDP:35661
Thanks for reply! Like 'fuser' 'lsof' gives an empty output. Jul 24, 2009 at 8:35
Pretty weird... You can also try to trace the pid and see if it shows something interesting: strace -p <PID>– scetoauxJul 24, 2009 at 8:58
1What PID, Fran?– innaMJul 24, 2009 at 9:24
Doh! True, we do not know the pid. Thanks for pointing it out Manni :)– scetoauxJul 24, 2009 at 9:26
lsofseems to usable only by root. My process is running as user "foo". I am user "foo", can get no results. Stragen. The tool
nestatshows the open ports.– guettliFeb 28, 2017 at 8:02
Did you run
netstat -tulp as
1Could have been the reason for the missing pid. You never know ;-)– innaMJul 24, 2009 at 9:22