ss Man page

SS(8) System Manager’s Manual SS(8)


ss – another utility to investigate sockets


ss [options] [ FILTER ]


ss is used to dump socket statistics. It allows showing information
similar to netstat. It can display more TCP and state informations
than other tools.


When no option is used ss displays a list of open non-listening sockets
(e.g. TCP/UNIX/UDP) that have established connection.

-h, –help
Show summary of options.

-V, –version
Output version information.

-n, –numeric
Do not try to resolve service names.

-r, –resolve
Try to resolve numeric address/ports.

-a, –all
Display both listening and non-listening (for TCP this means
established connections) sockets.

-l, –listening
Display only listening sockets (these are omitted by default).

-o, –options
Show timer information.

-e, –extended
Show detailed socket information

-m, –memory
Show socket memory usage.

-p, –processes
Show process using socket.

-i, –info
Show internal TCP information.

-s, –summary
Print summary statistics. This option does not parse socket
lists obtaining summary from various sources. It is useful when
amount of sockets is so huge that parsing /proc/net/tcp is

-Z, –context
As the -p option but also shows process security context.

For netlink(7) sockets the initiating process context is dis‐
played as follows:

1. If valid pid show the process context.

2. If destination is kernel (pid = 0) show kernel ini‐
tial context.

3. If a unique identifier has been allocated by the ker‐
nel or netlink user, show context as “unavailable”.
This will generally indicate that a process has more
than one netlink socket active.

-z, –contexts
As the -Z option but also shows the socket context. The socket
context is taken from the associated inode and is not the actual
socket context held by the kernel. Sockets are typically labeled
with the context of the creating process, however the context
shown will reflect any policy role, type and/or range transition
rules applied, and is therefore a useful reference.

-N NSNAME, –net=NS


Switch to the specified network namespace name.

-b, –bpf
Show socket BPF filters (only administrators are allowed to get
these information).

-4, –ipv4
Display only IP version 4 sockets (alias for -f inet).

-6, –ipv6
Display only IP version 6 sockets (alias for -f inet6).

-0, –packet
Display PACKET sockets (alias for -f link).

-t, –tcp
Display TCP sockets.

-u, –udp
Display UDP sockets.

-d, –dccp
Display DCCP sockets.

-w, –raw
Display RAW sockets.

-x, –unix
Display Unix domain sockets (alias for -f unix).

-f FAMILY, –family=FAMILY
Display sockets of type FAMILY. Currently the following fami‐
lies are supported: unix, inet, inet6, link, netlink.

-A QUERY, –query=QUERY, –socket=QUERY
List of socket tables to dump, separated by commas. The follow‐
ing identifiers are understood: all, inet, tcp, udp, raw, unix,
packet, netlink, unix_dgram, unix_stream, unix_seqpacket,
packet_raw, packet_dgram.

-D FILE, –diag=FILE
Do not display anything, just dump raw information about TCP
sockets to FILE after applying filters. If FILE is – stdout is

-F FILE, –filter=FILE
Read filter information from FILE. Each line of FILE is inter‐
preted like single command line option. If FILE is – stdin is

FILTER := [ state STATE-FILTER ] [ EXPRESSION ] Please take a look at the official documentation (Debian package
iproute-doc) for details regarding filters.

STATE-FILTER allows to construct arbitrary set of states to match. Its
syntax is sequence of keywords state and exclude followed by identifier
of state.

Available identifiers are:

All standard TCP states: established, syn-sent, syn-recv, fin-
wait-1, fin-wait-2, time-wait, closed, close-wait, last-ack,
listen and closing.

all – for all the states

connected – all the states except for listen and closed

synchronized – all the connected states except for syn-sent

bucket – states, which are maintained as minisockets, i.e.
time-wait and syn-recv

big – opposite to bucket

ss -t -a
Display all TCP sockets.

ss -t -a -Z
Display all TCP sockets with process SELinux security contexts.

ss -u -a
Display all UDP sockets.

ss -o state established ‘( dport = :ssh or sport = :ssh )’
Display all established ssh connections.

ss -x src /tmp/.X11-unix/*
Find all local processes connected to X server.

ss -o state fin-wait-1 ‘( sport = :http or sport = :https )’ dst
List all the tcp sockets in state FIN-WAIT-1 for our apache to
network 193.233.7/24 and look at their timers.


ip(8), /usr/share/doc/iproute-doc/ss.html (package iproutedoc),
RFC 793 – (TCP states)


ss was written by Alexey Kuznetsov, .

This manual page was written by Michael Prokop for the
Debian project (but may be used by others).