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BSD 2.11 - man page for netstat (bsd section 1)

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NETSTAT(1)									       NETSTAT(1)

NAME
       netstat - show network status

SYNOPSIS
       netstat [ -Aan ] [ -f address_family ] [ system ] [ core ]
       netstat [ -himnrs ] [ -f address_family ] [ system ] [ core ]
       netstat [ -n ] [ -I interface ] interval [ system ] [ core ]

DESCRIPTION
       The  netstat  command  symbolically  displays the contents of various network-related data
       structures.  There are a number of output formats, depending on the options for the infor-
       mation  presented.   The  first	form of the command displays a list of active sockets for
       each protocol.  The second form presents the contents of one of	the  other  network  data
       structures according to the option selected.  Using the third form, with an interval spec-
       ified, netstat will continuously display the information regarding packet traffic  on  the
       configured network interfaces.

       The options have the following meaning:

       -A     With  the  default display, show the address of any protocol control blocks associ-
	      ated with sockets; used for debugging.

       -a     With the default display, show the state of all sockets; normally sockets  used  by
	      server processes are not shown.

       -h     Show the state of the IMP host table.

       -i     Show the state of interfaces which have been auto-configured (interfaces statically
	      configured into a system, but not located at boot time are not shown).

       -I interface
	      Show information only about this interface; used	with  an  interval  as	described
	      below.

       -m     Show  statistics	recorded by the memory management routines (the network manages a
	      private pool of memory buffers).

       -n     Show network addresses  as  numbers  (normally  netstat  interprets  addresses  and
	      attempts	to  display  them symbolically).  This option may be used with any of the
	      display formats.

       -s     Show per-protocol statistics.

       -r     Show the routing tables.	When -s is also present, show routing statistics instead.

       -f address_family
	      Limit statistics or address  control  block  reports  to	those  of  the	specified
	      address family.	The following address families are recognized: inet, for AF_INET,
	      ns, for AF_NS, and unix, for AF_UNIX.

       The arguments, system  and  core  allow	substitutes  for  the  defaults  ``/vmunix''  and
       ``/dev/kmem''.

       The  default  display,  for active sockets, shows the local and remote addresses, send and
       receive queue sizes (in bytes), protocol, and the internal state of the protocol.  Address
       formats	are of the form ``host.port'' or ``network.port'' if a socket's address specifies
       a network but no specific host address.	When known the host  and  network  addresses  are
       displayed  symbolically	according to the data bases /etc/hosts and /etc/networks, respec-
       tively.	If a symbolic name for an address is unknown, or if the -n option  is  specified,
       the address is printed numerically, according to the address family.  For more information
       regarding the Internet ``dot format,'' refer to inet(3N).  Unspecified,	or  ``wildcard'',
       addresses and ports appear as ``*''.

       The  interface  display provides a table of cumulative statistics regarding packets trans-
       ferred, errors, and collisions.	The network addresses of the interface	and  the  maximum
       transmission unit (``mtu'') are also displayed.

       The  routing  table  display  indicates the available routes and their status.  Each route
       consists of a destination host or network and a gateway to use in forwarding packets.  The
       flags  field  shows  the  state	of the route (``U'' if ``up''), whether the route is to a
       gateway (``G''), and whether the route was created  dynamically	by  a  redirect  (``D'').
       Direct routes are created for each interface attached to the local host; the gateway field
       for such entries shows the address of the outgoing interface.  The refcnt field gives  the
       current	number	of active uses of the route.  Connection oriented protocols normally hold
       on to a single route for the duration  of  a  connection  while	connectionless	protocols
       obtain  a  route while sending to the same destination.	The use field provides a count of
       the number of packets sent using that route.  The interface entry  indicates  the  network
       interface utilized for the route.

       When  netstat is invoked with an interval argument, it displays a running count of statis-
       tics related to network interfaces.  This display consists of a	column	for  the  primary
       interface  (the	first  interface found during autoconfiguration) and a column summarizing
       information for all interfaces.	The primary interface may be replaced with another inter-
       face  with the -I option.  The first line of each screen of information contains a summary
       since the system was last rebooted.  Subsequent lines of output	show  values  accumulated
       over the preceding interval.

SEE ALSO
       iostat(1), vmstat(1), hosts(5), networks(5), protocols(5), services(5), trpt(8C)

BUGS
       The notion of errors is ill-defined.  Collisions mean something else for the IMP.

4.2 Berkeley Distribution		   May 8, 1986				       NETSTAT(1)
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