SS(8)                      System Manager's Manual                     SS(8)

NAME         top

       ss - another utility to investigate sockets

SYNOPSIS         top

       ss [options] [ FILTER ]

DESCRIPTION         top

       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.

OPTIONS         top

       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.

       -H, --no-header
              Suppress header line.

       -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.

       -K, --kill
              Attempts to forcibly close sockets. This option displays
              sockets that are successfully closed and silently skips
              sockets that the kernel does not support closing. It supports
              IPv4 and IPv6 sockets only.

       -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 painful.

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

              For netlink(7) sockets the initiating process context is
              displayed as follows:

                     1.  If valid pid show the process context.

                     2.  If destination is kernel (pid = 0) show kernel
                         initial context.

                     3.  If a unique identifier has been allocated by the
                         kernel 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=NSNAME
              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).

       -S, --sctp
              Display SCTP sockets.

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

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

       -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
              interpreted like single command line option. If FILE is -
              stdin is used.

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

STATE-FILTER         top

       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

USAGE EXAMPLES         top

       ss -t -a
              Display all TCP sockets.

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

       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.

SEE ALSO         top

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

AUTHOR         top

       ss was written by Alexey Kuznetsov, <>.

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

COLOPHON         top

       This page is part of the iproute2 (utilities for controlling TCP/IP
       networking and traffic) project.  Information about the project can
       be found at 
       If you have a bug report for this manual page, send it to,  This page was obtained
       from the project's upstream Git repository 
       on 2017-03-13.  If you discover any rendering problems in this HTML
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