I use a couple of different methods on a day to day basis to figure out what process has opened a port on my Linux machines. The first one works well in Linux, but doesn’t work in most Solaris versions I’ve sat down at
netstat -plate
This one is a bit more cross platform and uses lsof
lsof -Pani
Solaris tends to not install common tools like lsof, instead you have to go searching for them an install them yourself. Linux will spoil you, but Solaris is a necessary evil.