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NETSTAT(8)

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NAME    [Toc]    [Back]

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

SYNOPSIS    [Toc]    [Back]

       netstat	[address_family_options]  [--tcp|-t]   [--udp|-u]   [--raw|-w]
       [--listening|-l]     [--all|-a]	   [--numeric|-n]    [--numeric-hosts]
       [--numeric-ports]	   [--numeric-users]	       [--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-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]   [--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:

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

DESCRIPTION    [Toc]    [Back]

       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.

   --interface, -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    [Toc]    [Back]

   --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.

   -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 up

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

   -C
       Print routing information from the route cache.	UP.

OUTPUT    [Toc]    [Back]

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

   Recv-Q    [Toc]    [Back]
       The  count  of  bytes  not copied by the user program connected to this
       socket.

   Send-Q    [Toc]    [Back]
       The count of bytes not acknowledged by the remote host.

   Local Address    [Toc]    [Back]
       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    [Toc]    [Back]
       Address	and port number of the remote end of the socket.  Analogous to
       "Local Address."

   State    [Toc]    [Back]
       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 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    [Toc]    [Back]
       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    [Toc]    [Back]
       (this needs to be written)


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

   RefCnt    [Toc]    [Back]
       The reference count (i.e. attached processes via this socket).

   Flags    [Toc]    [Back]
       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    [Toc]    [Back]
       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    [Toc]    [Back]
       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    [Toc]    [Back]
       This is the path name as which the corresponding processes attached  to
       the socket.


   Active IPX sockets    [Toc]    [Back]
       (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    [Toc]    [Back]
       (this needs to be done by somebody who knows it)

NOTES    [Toc]    [Back]

       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    [Toc]    [Back]

       /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    [Toc]    [Back]

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

BUGS    [Toc]    [Back]

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

AUTHORS    [Toc]    [Back]

       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@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		       24 November 2001 		    NETSTAT(8)
[ Back ]
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