Linux; How do I find logs if a program I'm running uses certain ports?

Question

I am running CentOS 5 with csf firewall. I'm running a program that can't connect to another server (using some port that is blocked by csf I presume). Where is the log file for 'ports'?

Answer 1

Netstat is the command to use to get ports and network activity. To diagonise server processes I usually use:

netstat -tln

This yields port numbers in tcp mode listening. To identify associated processes you can also use -p to grab the pid. Here is the IANA ports list.

Answer 2

I found my answer right after searching a few more threads.

# tail -f /var/log/messages

Shows the UDP message but not the port.... Hmm....