How to find ports opened by process ID in Linux?

Question

Suppose the PID of the process is already known

Answer 1

You can use the command below:

lsof -i -P |grep pid 

Answer 2

netstat --all --program | grep '3265' 

• --all show listening and non-listening sockets.
  
• --program show the PID and name of the program to which socket belongs.

You could also use a port scanner such as Nmap.