netstat(8) — Linux manual page


NETSTAT(8)           Linux System Administrator's Manual          NETSTAT(8)

NAME         top

       netstat  -  Print network connections, routing tables, interface sta‐
       tistics, masquerade connections, and multicast memberships

SYNOPSIS         top

       netstat [address_family_options] [--tcp|-t] [--udp|-u] [--udplite|-U]
       [--sctp|-S] [--raw|-w] [--l2cap|-2] [--rfcomm|-f] [--listening|-l]
       [--all|-a] [--numeric|-n] [--numeric-hosts] [--numeric-ports]
       [--numeric-users] [--symbolic|-N] [--extend|-e[--extend|-e]]
       [--timers|-o] [--program|-p] [--verbose|-v] [--continuous|-c]

       netstat {--route|-r} [address_family_options]
       [--extend|-e[--extend|-e]] [--verbose|-v] [--numeric|-n]
       [--numeric-hosts] [--numeric-ports] [--numeric-users]

       netstat {--interfaces|-i} [--all|-a] [--extend|-e[--extend|-e]]
       [--verbose|-v] [--program|-p] [--numeric|-n] [--numeric-hosts]
       [--numeric-ports] [--numeric-users] [--continuous|-c]

       netstat {--groups|-g} [--numeric|-n] [--numeric-hosts]
       [--numeric-ports] [--numeric-users] [--continuous|-c]

       netstat {--masquerade|-M} [--extend|-e] [--numeric|-n]
       [--numeric-hosts] [--numeric-ports] [--numeric-users]

       netstat {--statistics|-s} [--tcp|-t] [--udp|-u] [--udplite|-U]
       [--sctp|-S] [--raw|-w]

       netstat {--version|-V}

       netstat {--help|-h}


       [-4|--inet] [-6|--inet6]
       [--protocol={inet,inet6,unix,ipx,ax25,netrom,ddp,bluetooth, ... } ]
       [--unix|-x] [--inet|--ip|--tcpip] [--ax25] [--x25] [--rose] [--ash]
       [--bluetooth] [--ipx] [--netrom] [--ddp|--appletalk] [--econet|--ec]

NOTES         top

       This program is mostly obsolete.  Replacement for netstat is ss.
       Replacement for netstat -r is ip route.  Replacement for netstat -i
       is ip -s link.  Replacement for netstat -g is ip maddr.

DESCRIPTION         top

       Netstat prints information about the Linux networking subsystem.  The
       type of information printed is controlled by the first argument, as

       By default, netstat displays a list of open sockets.  If you don't
       specify any address families, then the active sockets of all
       configured address families will be printed.

   --route, -r
       Display the kernel routing tables. See the description in route(8)
       for details.  netstat -r and route -e produce the same output.

   --groups, -g
       Display multicast group membership information for IPv4 and IPv6.

   --interfaces, -i
       Display a table of all network interfaces.

   --masquerade, -M
       Display a list of masqueraded connections.

   --statistics, -s
       Display summary statistics for each protocol.

OPTIONS         top

   --verbose, -v
       Tell the user what is going on by being verbose. Especially print
       some useful information about unconfigured address families.

   --wide, -W
       Do not truncate IP addresses by using output as wide as needed. This
       is optional for now to not break existing scripts.

   --numeric, -n
       Show numerical addresses instead of trying to determine symbolic
       host, port or user names.

       shows numerical host addresses but does not affect the resolution of
       port or user names.

       shows numerical port numbers but does not affect the resolution of
       host or user names.

       shows numerical user IDs but does not affect the resolution of host
       or port names.

   --protocol=family, -A
       Specifies the address families (perhaps better described as low level
       protocols) for which connections are to be shown.  family is a comma
       (',') separated list of address family keywords like inet, inet6,
       unix, ipx, ax25, netrom, econet, ddp, and bluetooth.  This has the
       same effect as using the --inet|-4, --inet6|-6, --unix|-x, --ipx,
       --ax25, --netrom, --ddp, and --bluetooth options.

       The address family inet (Iv4) includes raw, udp, udplite and tcp
       protocol sockets.

       The address family bluetooth (Iv4) includes l2cap and rfcomm protocol

   -c, --continuous
       This will cause netstat to print the selected information every
       second continuously.

   -e, --extend
       Display additional information.  Use this option twice for maximum

   -o, --timers
       Include information related to networking timers.

   -p, --program
       Show the PID and name of the program to which each socket belongs.

   -l, --listening
       Show only listening sockets.  (These are omitted by default.)

   -a, --all
       Show both listening and non-listening sockets.  With the --interfaces
       option, show interfaces that are not up

       Print routing information from the FIB.  (This is the default.)

       Print routing information from the route cache.

OUTPUT         top

   Active Internet connections (TCP, UDP, UDPLite, raw)
       The protocol (tcp, udp, udpl, raw) used by the socket.

       Established: The count of bytes not copied by the user program
       connected to this socket.  Listening: Since Kernel 2.6.18 this column
       contains the current syn backlog.

       Established: The count of bytes not acknowledged by the remote host.
       Listening: Since Kernel 2.6.18 this column contains the maximum size
       of the syn backlog.

   Local Address
       Address and port number of the local end of the socket.  Unless the
       --numeric (-n) option is specified, the socket address is resolved to
       its canonical host name (FQDN), and the port number is translated
       into the corresponding service name.

   Foreign Address
       Address and port number of the remote end of the socket.  Analogous
       to "Local Address".

       The state of the socket. Since there are no states in raw mode and
       usually no states used in UDP and UDPLite, this column may be left
       blank. Normally this can be one of several values:

              The socket has an established connection.

              The socket is actively attempting to establish a connection.

              A connection request has been received from the network.

              The socket is closed, and the connection is shutting down.

              Connection is closed, and the socket is waiting for a shutdown
              from the remote end.

              The socket is waiting after close to handle packets still in
              the network.

       CLOSE  The socket is not being used.

              The remote end has shut down, waiting for the socket to close.

              The remote end has shut down, and the socket is closed.
              Waiting for acknowledgement.

       LISTEN The socket is listening for incoming connections.  Such
              sockets are not included in the output unless you specify the
              --listening (-l) or --all (-a) option.

              Both sockets are shut down but we still don't have all our
              data sent.

              The state of the socket is unknown.

       The username or the user id (UID) of the owner of the socket.

   PID/Program name
       Slash-separated pair of the process id (PID) and process name of the
       process that owns the socket.  --program causes this column to be
       included.  You will also need superuser privileges to see this
       information on sockets you don't own.  This identification
       information is not yet available for IPX sockets.

       (this needs to be written)

   Active UNIX domain Sockets
       The protocol (usually unix) used by the socket.

       The reference count (i.e. attached processes via this socket).

       The flags displayed is SO_ACCEPTON (displayed as ACC), SO_WAITDATA
       (W) or SO_NOSPACE (N).  SO_ACCECPTON is used on unconnected sockets
       if their corresponding processes are waiting for a connect request.
       The other flags are not of normal interest.

       There are several types of socket access:

              The socket is used in Datagram (connectionless) mode.

              This is a stream (connection) socket.

              The socket is used as a raw socket.

              This one serves reliably-delivered messages.

              This is a sequential packet socket.

              Raw interface access socket.

              Who ever knows what the future will bring us - just fill in
              here :-)

       This field will contain one of the following Keywords:

       FREE   The socket is not allocated

              The socket is listening for a connection request.  Such
              sockets are only included in the output if you specify the
              --listening (-l) or --all (-a) option.

              The socket is about to establish a connection.

              The socket is connected.

              The socket is disconnecting.

              The socket is not connected to another one.

              This state should never happen.

   PID/Program name
       Process ID (PID) and process name of the process that has the socket
       open.  More info available in Active Internet connections section
       written above.

       This is the path name as which the corresponding processes attached
       to the socket.

   Active IPX sockets
       (this needs to be done by somebody who knows it)

   Active NET/ROM sockets
       (this needs to be done by somebody who knows it)

   Active AX.25 sockets
       (this needs to be done by somebody who knows it)

FILES         top

       /etc/services -- The services translation file

       /proc -- Mount point for the proc filesystem, which gives access to
       kernel status information via the following files.

       /proc/net/dev -- device information

       /proc/net/raw -- raw socket information

       /proc/net/tcp -- TCP socket information

       /proc/net/udp -- UDP socket information

       /proc/net/udplite -- UDPLite socket information

       /proc/net/igmp -- IGMP multicast information

       /proc/net/unix -- Unix domain socket information

       /proc/net/ipx -- IPX socket information

       /proc/net/ax25 -- AX25 socket information

       /proc/net/appletalk -- DDP (appletalk) socket information

       /proc/net/nr -- NET/ROM socket information

       /proc/net/route -- IP routing information

       /proc/net/ax25_route -- AX25 routing information

       /proc/net/ipx_route -- IPX routing information

       /proc/net/nr_nodes -- NET/ROM nodelist

       /proc/net/nr_neigh -- NET/ROM neighbours

       /proc/net/ip_masquerade -- masqueraded connections

       /sys/kernel/debug/bluetooth/l2cap -- Bluetooth L2CAP information

       /sys/kernel/debug/bluetooth/rfcomm -- Bluetooth serial connections

       /proc/net/snmp -- statistics

SEE ALSO         top

       route(8), ifconfig(8), iptables(8), proc(5) ss(8) ip(8)

BUGS         top

       Occasionally strange information may appear if a socket changes as it
       is viewed. This is unlikely to occur.

AUTHORS         top

       The netstat user interface was written by Fred Baumgarten
       <>, the man page basically by Matt
       Welsh <>. It was updated by Alan Cox
       <>, updated again by Tuan Hoang
       <>. The man page and the command included in the
       net-tools package is totally rewritten by Bernd Eckenfels
       <>.  UDPLite options were added by Brian Micek

COLOPHON         top

       This page is part of the net-tools (networking utilities) project.
       Information about the project can be found at 
       ⟨⟩.  If you have a bug report for
       this manual page, see ⟨⟩.  This page
       was obtained from the project's upstream Git repository
       ⟨git://⟩ on 2020-09-18.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2018-11-03.)  If you discover any rendering problems in
       this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not part
       of the original manual page), send a mail to

net-tools                        2014-10-07                       NETSTAT(8)

Pages that refer to this page: networks(5)proc(5)procfs(5)icmp(7)arp(8)ifconfig(8)netcap(8)rarp(8)route(8)traceroute(8)