Network

The ss command

Lists the connections and ports listening on your machine.

Syntax

ss [-tulpn]

Most useful options

-tTCP connections
-uUDP connections
-lOnly listening ports
-pThe process owning each port

Copy-ready examples

$ ss -tulpnWhat is listening on my machine
$ ss -tOnly TCP connections

You can try them in the browser terminal: it does not touch your computer.

Typical mistakes

  • Knowing what listens is the first step to closing ports left open.

Related commands

FAQ

What does LISTEN mean?

That a program is waiting for connections on that port.

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