Use Netstat on Linux to view current service and listening ports

Netstat This command is commonly used in network monitoring. With this command, you can view the current system listening services and established services, as well as the corresponding ports, protocols and other information.

Netstat parameter description

Netstat parameters, although a lot, but often not much, mainly the following several parameters:

Netstat-[ATUNLP]

• -a:all, indicating that all connections, service monitoring, socket data are listed
• -T:TCP, listing services for the TCP protocol
• -U:UDP, listing services for UDP protocol
• -n:port number, which is displayed using the port
• -l:listening, list the current listening service
• -p:program, list the PID of the service program

If you need more insight, you can use the man netstat to see a detailed description of the netstat command.

Netstat command test

Netstat-atunlp

Output results such as

Netstat command demo

which

• Proto: Network transport protocol, mainly for TCP and UDP
• Local Address: Ip:port
• Foreign Address: remote host's Ip:port
• State: Connection status, mainly monitored (LISTEN) and established (establised)
• PID: Process number of the service
• Program Name: Service names

The status of the penultimate line above is establised because I am currently using putty to connect to this host.

Use Netstat on Linux to view current service and listening ports