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.
Show summary of options.
Output version information.
Do not try to resolve service names.
Try to resolve numeric address/ports.
Display both listening and non-listening (for TCP this means
established connections) sockets.
Display only listening sockets (these are omitted by default).
Show timer information.
Show detailed socket information
Show socket memory usage.
Show process using socket.
Show internal TCP information.
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
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‐
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.
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.
Show socket BPF filters (only administrators are allowed to get
Display only IP version 4 sockets (alias for -f inet).
Display only IP version 6 sockets (alias for -f inet6).
Display PACKET sockets (alias for -f link).
Display TCP sockets.
Display UDP sockets.
Display DCCP sockets.
Display RAW sockets.
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,
-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
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 – https://tools.ietf.org/rfc/rfc793.txt (TCP states)
ss was written by Alexey Kuznetsov,
This manual page was written by Michael Prokop
Debian project (but may be used by others).