8:netstat

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Contents 1 NAME 2 SYNOPSIS 3 DESCRIPTION 4 (none) 5 --route , -r 6 --groups , -g 7 --interfaces , -i 8 --masquerade , -M 9 --statistics , -s 9.1 OPTIONS 10 --verbose , -v 11 --numeric , -n 12 --numeric-hosts 13 --numeric-ports 14 --numeric-users 15 --protocol=family , -A 16 -c, --continuous 17 -e, --extend 18 -o, --timers 19 -p, --program 20 -l, --listening 21 -a, --all 22 -F 23 -C 23.1 OUTPUT 24 Proto 25 Recv-Q 26 Send-Q 27 Local Address 28 Foreign Address 29 State 30 User 31 PID/Program name 32 Timer 33 Active UNIX domain Sockets 34 Proto 35 RefCnt 36 Flags 37 Type 38 State 39 PID/Program name 40 Path 41 Active IPX sockets 42 Active NET/ROM sockets 43 Active AX.25 sockets 43.1 NOTES 43.2 FILES 43.3 RELATED 43.4 BUGS 43.5 CATEGORY

NAME

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

SYNOPSIS

      netstat  [address_family_options]  [--tcp|-t]   [--udp|-u]   [--raw|-w]
      [--listening|-l] [--all|-a] [--numeric|-n] [--numeric-hosts][--numeric-
      ports][--numeric-ports]   [--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-ports] [--continuous|-c]
 
      netstat [--interfaces|-i] [--all|-a] [--extend|-e[--extend|-e]] [--ver-
      bose|-v]  [--program|-p]  [--numeric|-n]   [--numeric-hosts][--numeric-
      ports][--numeric-ports] [--continuous|-c]
 
      netstat   {--groups|-g}   [--numeric|-n]   [--numeric-hosts][--numeric-
      ports][--numeric-ports] [--continuous|-c]
 
      netstat  {--masquerade|-M}  [--extend|-e]  [--numeric|-n]   [--numeric-
      hosts][--numeric-ports][--numeric-ports] [--continuous|-c]
 
      netstat {--statistics|-s} [--tcp|-t] [--udp|-u] [--raw|-w]
 
      netstat {--version|-V}
 
      netstat {--help|-h}
 
      address_family_options:
 
      [--protocol={inet,unix,ipx,ax25,netrom,ddp}[,...]]          [--unix|-x]
      [--inet|--ip] [--ax25] [--ipx] [--netrom] [--ddp]

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.

--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.

--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, unix, ipx,
      ax25, netrom, and ddp.  This has the same effect as using  the  --inet,
      --unix (-x), --ipx, --ax25, --netrom, and --ddp options.
 
      The address family inet includes raw, udp and tcp protocol sockets.

-c, --continuous

      This  will cause netstat to print the selected information every second
      continuously. The values are just increments of the last print out.

-e, --extend

      Display additional information.  Use  this  option  twice  for  maximum
      detail.

-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 marked

-F

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

-C

      Print routing information from the route cache.  UP.

OUTPUT

  Active Internet connections (TCP, UDP, raw)

Proto

      The protocol (tcp, udp, raw) used by the socket.

Recv-Q

      The count of bytes not copied by the user  program  connected  to  this
      socket.

Send-Q

      The count of bytes not acknowledged by the remote host.

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, 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.
 
      CLOSED 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
      included.  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)

NOTES

      Starting with Linux release 2.2 netstat  -i  does  not  show  interface
      statistics  for  alias  interfaces. To get per alias interface counters
      you need to setup explicit rules using the ipchains(8) command.

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/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
 
      /proc/net/snmp -- statistics

RELATED

      route(8), ifconfig(8), ipchains(8), iptables(8), proc(5)

BUGS

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

CATEGORY