This is a quick guide to some not so obvious command-line options available in the Linux netstat command. I hope you enjoy it.
1. Plain old netstat
Without any command-line arguments, “netstat” shows a list of network connections in your system, including TCP, UDP and UNIX socket connections.
If you want to speed up things a bit, use “-n” (numeric) to prevent network lookups and display IP and port numbers instead of names.
2. Seeing all connections with “netstat -a”
Full Story .