Port listening via netstat command for network monitoring

General
1

Sir, I need your guidelines to better understand the netstat command for port listening. Please let me know what is the purpose and meaning of*:*and [::] in port listening? I want a deep understanding on it.

2 
netstat -tulpn
  • -t: Shows TCP connections.
  • -u: Shows UDP connections.
  • -l: Displays listening sockets.
  • -p: Shows the process ID and name that owns the socket.
  • -n: Displays numerical addresses and port numbers.

This command will provide you with a list of all active TCP and UDP connections, along with the corresponding process ID and name. It will also show which sockets are in a listening state.

3

The : in port listening represents all IP addresses and all ports. It means that the socket is listening on all available network interfaces and any incoming traffic to any port will be accepted.

The [::] in port listening represents an IPv6 address and all ports. It means that the socket is listening on all available IPv6 network interfaces and any incoming traffic to any port will be accepted.