Networking

Linux ss command

Show socket information. The flags below list listening TCP and UDP ports.

Availability: Common Linux commands; shell built-ins and external implementations may differ by distribution.中文

Syntax

ss [OPTIONS] [FILTER]

Examples

Show listening TCP/UDP sockets and associated processes.

ss -tulpn

List established TCP connections numerically.

ss -tan state established

Parameters, options and clauses

Option / clause	Description
`-t, --tcp`	Display TCP sockets.
`-u, --udp`	Display UDP sockets.
`-l, --listening`	Display listening sockets.
`-n, --numeric`	Do not resolve service names or addresses.
`-p, --processes`	Show the process using each socket (permissions may limit details).
`-a, --all`	Display listening and non-listening sockets.
`-s, --summary`	Print socket usage summary.

Safety note

Review a command and its target before running it. Commands that alter files, services, accounts, disks, permissions or databases may be difficult to reverse. Test in a safe environment and keep backups.

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