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Linux 2.6 - man page for netstat (linux section 8)

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

NAME
       netstat - Print network connections, routing tables, interface statistics, masquerade con-
       nections, 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-users] [--sym-
       bolic|-N] [--extend|-e[--extend|-e]] [--timers|-o] [--program|-p]  [--verbose|-v]  [--con-
       tinuous|-c]

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

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

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

       netstat {--version|-V}

       netstat {--help|-h}

       address_family_options:

       [-4] [-6]  [--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. 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, 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
       Show only listening sockets.  (These are omitted by default.)

   -a, --all
       Show  both listening and non-listening sockets.	With the --interfaces option, show inter-
       faces 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, 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 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 acknowledge-
	      ment.

       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 privi-
       leges  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.

       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 informa-
       tion 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
       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-karls-
       ruhe.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@bigfoot.com>.
       The  man  page  and  the command included in the net-tools package is totally rewritten by
       Bernd Eckenfels <ecki@linux.de>.

net-tools				    2008-11-16				       NETSTAT(8)


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