# 2.11BSD#431 - /usr/man/cat1/netstat.0

    NETSTAT(1)	    UNIX Programmer's Manual	       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 informa-
         tion 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 specified, netstat will con-
         tinuously 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 pro-
    	  tocol control blocks associated with sockets; used for
    	  debugging.

         -a   With the default display, show the state of all sock-
    	  ets; 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 rou-
    	  tines (the network manages a private pool of memory
    	  buffers).

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

         -s   Show per-protocol statistics.

    Printed 11/26/99	   May 8, 1986				1

    NETSTAT(1)	    UNIX Programmer's Manual	       NETSTAT(1)

         -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, respectively.  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 statis-
         tics regarding packets transferred, 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 statistics related to network
         interfaces.  This display consists of a column for the pri-
         mary interface (the first interface found during

    Printed 11/26/99	   May 8, 1986				2

    NETSTAT(1)	    UNIX Programmer's Manual	       NETSTAT(1)

         autoconfiguration) and a column summarizing information for
         all interfaces.  The primary interface may be replaced with
         another interface with the -I option.  The first line of
         each screen of information contains a summary since the sys-
         tem 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 some-
         thing else for the IMP.

    Printed 11/26/99	   May 8, 1986				3

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