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April, 26th. 2006:
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SS
Section: Maintenance Commands (8) Index
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NAME
ss - another utility to investigate sockets
SYNOPSIS
ss
[ options] [ FILTER ]
DESCRIPTION
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
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 used.
- -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
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,
listening and closing.
all
- for all the states
connected
- all the states except for
listening 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
- 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 193.233.7/24
-
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
ip(8),
/usr/share/doc/iproute-doc/ss.html (package iproutedoc),
RFC 793
- https://tools.ietf.org/rfc/rfc793.txt (TCP states)
AUTHOR
ss
was written by Alexey Kuznetsov, < kuznet@ms2.inr.ac.ru>.
This manual page was written by Michael Prokop <mika@grml.org>
for the Debian project (but may be used by others).
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- OPTIONS
-
- STATE-FILTER
-
- USAGE EXAMPLES
-
- SEE ALSO
-
- AUTHOR
-
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