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netstat


       cast 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}      [iface]      [--all|-a]
       [--extend|-e[--extend|-e]]  [--verbose|-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 sub­
       system.   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 summary statistics for each protocol.


OPTIONS

   --verbose , -v
       Tell  the  user  what  is going on by being verbose. Espe­
       cially 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 reso­
       lution of host or user names.

   --numeric-users
       shows numerical user IDs but does not affect  the  resolu­
       tion 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.

   -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


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 con­
       nected 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 ser­
       vice 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 usually 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 shut­
              ting 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.


       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  information  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.

   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 written 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.

       /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


SEE ALSO

       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.


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> but could  do  with  a  bit  more
       work.   It  was  updated again by Tuan Hoang <tqhoang@big­
       foot.com>.
       The man page and the command  included  in  the  net-tools
       package   is   totally   rewritten   by   Bernd  Eckenfels
       <ecki@linux.de>.

  

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