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NETSTAT(8)                 Linux Programmer's Manual                NETSTAT(8)



NAME
       netstat - Print network connections, routing tables, interface statistics, masquer-
       ade 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]  [--ver-
       bose|-v] [--continuous|-c] [delay]

       netstat  {--route|-r}  [address_family_options]  [--extend|-e[--extend|-e]] [--ver-
       bose|-v] [--numeric|-n] [--numeric-hosts][--numeric-ports][--numeric-ports] [--con-
       tinuous|-c] [delay]

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

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

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

       netstat {--statistics|-s} [--tcp|-t] [--udp|-u] [--raw|-w] [delay]

       netstat {--version|-V}

       netstat {--help|-h}

       address_family_options:

       [--protocol={inet,inet6,unix,ipx,ax25,netrom,ddp, ... } ] [--unix|-x] [--inet|--ip]
       [--ax25] [--ipx] [--netrom] [--ddp]


NOTE
       This program is obsolete.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
       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=iface , -I=iface , -i
       Display a table of all network interfaces, or the specified iface.

   --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, inet6, unix, ipx, ax25, netrom, and  ddp.   This
       has  the  same  effect  as  using  the --inet, --inet6, --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  continu-
       ously.

   -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 (for TCP this means established connections)
       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.

   -Z --context
       If SELinux enabled print SELinux context.

   -T --notrim
       Stop trimming long addresses.

   delay
       Netstat will cycle printing through statistics every delay seconds.  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 usually no
       states used in UDP, this column may be left blank. Normally this can be one of sev-
       eral 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 acknowl-
              edgement.

       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.

       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 iden-
       tification 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 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.


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



SEE ALSO
       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 AT insu1.uni-
       karlsruhe.de> the man page basically by Matt  Welsh  <mdw AT tc.edu>.  It  was
       updated by Alan Cox <Alan.Cox AT linux.org> but could do with a bit more work.  It was
       updated again by Tuan Hoang <tqhoang AT bigfoot.com>.
       The man page and the command included in the net-tools package is totally rewritten
       by Bernd Eckenfels <ecki AT linux.de>.



net-tools                      19 December 2000                     NETSTAT(8)

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