systemctl-list-sockets

List active socket units

$ systemctl list-sockets

$ systemctl list-sockets --show-types

$ systemctl list-sockets -a

$ systemctl list-sockets --state [active|inactive|failed]

$ systemctl list-sockets [pattern]

systemctl list-sockets [OPTIONS] [PATTERN...]

systemctl list-sockets displays socket units currently active in memory, ordered by listening address. Socket units implement socket activation, where services are started on-demand when connections arrive.
The output shows the listening address (IP:port, path, etc.), the socket unit name, and the unit it activates.

-a, --all

Include inactive and failed socket units

Filter by state

Display socket types (Stream, Datagram, etc.)

Suppress header and footer

Disable pager

Shows systemd-managed sockets only, not all listening sockets on the system. Use `ss` or `netstat` for a complete list. Socket activation may cause startup delays on first connection.

The list-sockets subcommand provides insight into systemd's socket activation infrastructure, which reduces memory usage by starting services only when needed.

systemctl-list-units(1), systemd.socket(5), ss(8)