Identify which process is using a port

Linux:
Use the lsof command and grep for the port number you are interested in:

sharfah@starship:~>  lsof -Pan -i tcp -i udp | grep :8343
java    27725 sharfah    6u  IPv6 20486040       TCP *:8343 (LISTEN)

Solaris:
If you have lsof installed on Solaris, then you can use the Linux method above. If you don't have or cannot install lsof, then use the pre-installed pfiles in a loop, as shown below:

sharfah@starship:~>  ps -ef | grep myuser | awk '{print $2}' | while read pid
>do
>echo $pid
>pfiles $pid| grep 12197
>done
19424
16132
16040
29373
15946
25178
 121: S_IFREG mode:0640 dev:289,6 ino:259883 uid:50006 gid:106 size:109318
        peername: AF_INET 10.232.160.164  port: 12197
        peername: AF_INET 10.232.160.164  port: 12197
        peername: AF_INET 10.232.160.164  port: 12197
        peername: AF_INET 10.232.160.164  port: 12197
        peername: AF_INET 10.232.160.164  port: 12197
        peername: AF_INET 10.232.160.164  port: 12197
        peername: AF_INET 10.232.160.164  port: 12197
        peername: AF_INET 10.232.160.164  port: 12197
        peername: AF_INET 10.232.160.164  port: 12197
        peername: AF_INET 10.232.160.164  port: 12197
15985
16052
18758