netstat

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

NAME
       netstat  - Print network connections, routing tables, interface statis-
       tics, masquerade connections, and multicast memberships

SYNOPSIS
       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]  [--nu-
       meric-users]  [--symbolic|-N]  [--extend|-e[--extend|-e]] [--timers|-o]
       [--program|-p] [--verbose|-v] [--continuous|-c] [--wide|-W]

       netstat   {--route|-r}   [address_family_options]    [--extend|-e[--ex-
       tend|-e]]   [--verbose|-v]   [--numeric|-n]   [--numeric-hosts]  [--nu-
       meric-ports] [--numeric-users] [--continuous|-c]

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

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

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

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

       netstat {--version|-V}

       netstat {--help|-h}

       address_family_options:

       [-4|--inet]                    [-6|--inet6]                   [--proto-
       col={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
       This program is mostly obsolete.  Replacement for netstat is  ss.   Re-
       placement for netstat -r is ip route.  Replacement for netstat -i is ip
       -s link.  Replacement for netstat -g is ip maddr.

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

   (none)
       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
   --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.

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

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

   --numeric-users
       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  ef-
       fect  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 proto-
       col sockets.

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

   -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 de-
       tail.

   -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

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

   -C
       Print routing information from the route cache.

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

   Recv-Q
       Established:  The  count  of  bytes not copied by the user program con-
       nected to this socket.  Listening: Since Kernel 2.6.18 this column con-
       tains the current syn backlog.

   Send-Q
       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".

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

       ESTABLISHED
              The socket has an established connection.

       SYN_SENT
              The socket is actively attempting to establish a connection.

       SYN_RECV
              A connection request has been received from the network.

       FIN_WAIT1
              The socket is closed, and the connection is shutting down.

       FIN_WAIT2
              Connection  is  closed, and the socket is waiting for a shutdown
              from the remote end.

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

       CLOSE  The socket is not being used.

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

       LAST_ACK
              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 --listen-
              ing (-l) or --all (-a) option.

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

       UNKNOWN
              The state of the socket is unknown.

   User
       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  in-
       cluded.   You  will also need superuser privileges to see this informa-
       tion on sockets you don't own.  This identification information is  not
       yet available for IPX sockets.

   Timer
       (this needs to be written)

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

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

   Flags
       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.

   Type
       There are several types of socket access:

       SOCK_DGRAM
              The socket is used in Datagram (connectionless) mode.

       SOCK_STREAM
              This is a stream (connection) socket.

       SOCK_RAW
              The socket is used as a raw socket.

       SOCK_RDM
              This one serves reliably-delivered messages.

       SOCK_SEQPACKET
              This is a sequential packet socket.

       SOCK_PACKET
              Raw interface access socket.

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

   State
       This field will contain one of the following Keywords:

       FREE   The socket is not allocated

       LISTENING
              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.

       CONNECTING
              The socket is about to establish a connection.

       CONNECTED
              The socket is connected.

       DISCONNECTING
              The socket is disconnecting.

       (empty)
              The socket is not connected to another one.

       UNKNOWN
              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 writ-
       ten above.

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

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

AUTHORS
       The  netstat  user   interface   was   written   by   Fred   Baumgarten
       <dc6iq@insu1.etec.uni-karlsruhe.de>,  the  man  page  basically by Matt
       Welsh   <mdw@tc.cornell.edu>.   It   was   updated    by    Alan    Cox
       <Alan.Cox@linux.org>,   updated   again  by  Tuan  Hoang  <tqhoang@big-
       foot.com>. The man page and the command included in the net-tools pack-
       age  is  totally rewritten by Bernd Eckenfels <ecki@linux.de>.  UDPLite
       options were added by Brian Micek <bmicek@gmail.com>

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