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NETSTAT(1)		  BSD General Commands Manual		    NETSTAT(1)

NAME
     netstat — show network status

SYNOPSIS
     netstat [-AaLlnW] [-f address_family | -p protocol] [-M core] [-N system]
     netstat [-gilns] [-f address_family] [-M core] [-N system]
     netstat -i | -I interface [-w wait] [-abdgt] [-M core] [-N system]
     netstat -s [-s] [-f address_family | -p protocol] [-M core] [-N system]
     netstat -i | -I interface -s [-f address_family | -p protocol] [-M core]
	     [-N system]
     netstat -m [-M core] [-N system]
     netstat -r [-Aaln] [-f address_family] [-M core] [-N system]
     netstat -rs [-s] [-M core] [-N system]

DESCRIPTION
     The netstat command symbolically displays the contents of various net‐
     work-related data structures.  There are a number of output formats,
     depending on the options for the information 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 struc‐
     tures according to the option selected. Using the third form, with a wait
     interval specified, netstat will continuously display the information
     regarding packet traffic on the configured network interfaces.  The
     fourth form displays statistics for the specified protocol or address
     family.  The fifth form displays per-interface statistics for the speci‐
     fied protocol or address family.  The sixth form displays mbuf(9) statis‐
     tics.  The seventh form displays routing table for the specified address
     family.  The eighth form displays routing statistics.

     The options have the following meaning:

     -A	   With the default display, show the address of any protocol control
	   blocks associated 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. With the routing
	   table display (option -r, as described below), show protocol-cloned
	   routes (routes generated by a RTF_PRCLONING parent route); normally
	   these routes are not shown.

     -b	   With the interface display (option -i, as described below), show
	   the number of bytes in and out.

     -d	   With either interface display (option -i or an interval, as
	   described below), show the number of dropped packets.

     -f address_family
	   Limit statistics or address control block reports to those of the
	   specified address family.  The following address families are rec‐
	   ognized: inet, for AF_INET, inet6, for AF_INET6 and unix, for
	   AF_UNIX.

     -g	   Show information related to multicast (group address) routing.  By
	   default, show the IP Multicast virtual-interface and routing
	   tables. If the -s option is also present, show multicast routing
	   statistics.

     -I interface
	   Show information about the specified interface; used with a wait
	   interval as described below.	 If the -s option is present, show
	   per-interface protocol statistics on the interface for the speci‐
	   fied address_family or protocol, or for all protocol families.

     -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).  If the -a options is also present, mul‐
	   ticast addresses currently in use are shown for each Ethernet
	   interface and for each IP interface address.	 Multicast addresses
	   are shown on separate lines following the interface address with
	   which they are associated.  If the -s option is present, show per-
	   interface statistics on all interfaces for the specified
	   address_family or protocol, or for all protocol families.

     -L	   Show the size of the various listen queues.	The first count shows
	   the number of unaccepted connections.  The second count shows the
	   amount of unaccepted incomplete connections.	 The third count is
	   the maximum number of queued connections.

     -l	   Print full IPv6 address.

     -M	   Extract values associated with the name list from the specified
	   core instead of the default /dev/kmem.

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

     -N	   Extract the name list from the specified system instead of the
	   default /kernel.

     -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.

     -p protocol
	   Show statistics about protocol, which is either a well-known name
	   for a protocol or an alias for it.  Some protocol names and aliases
	   are listed in the file /etc/protocols.  The special protocol name
	   “bdg” is used to show bridging statistics.  A null response typi‐
	   cally means that there are no interesting numbers to report.	 The
	   program will complain if protocol is unknown or if there is no sta‐
	   tistics routine for it.

     -r	   Show the routing tables.  Use with -a to show protocol-cloned
	   routes.  When -s is also present, show routing statistics instead.
	   When -l is also present, netstat assumes more columns are there and
	   the maximum transmission unit (“mtu”) are also displayed.

     -s	   Show per-protocol statistics.  If this option is repeated, counters
	   with a value of zero are suppressed.

     -W	   In certain displays, avoid truncating addresses even if this causes
	   some fields to overflow.

     -w wait
	   Show network interface statistics at intervals of wait seconds.

OUTPUT
     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.  If known, the host and network addresses
     are displayed symbolically according to the databases /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 numeri‐
     cally, according to the address family.  For more information regarding
     the Internet “dot format”, refer to inet(3)).  Unspecified, or
     “wildcard”, addresses and ports appear as “*”.

     Internet domain socket states:

     CLOSED:  The socket is not in use.

     LISTEN:  The socket is listening for incoming connections.	 Unconnected
     listening sockets like these are only displayed when using the -a option.

     SYN_SENT:	The socket is actively trying to establish a connection to a
     remote peer.

     SYN_RCVD:	The socket has passively received a connection request from a
     remote peer.

     ESTABLISHED:  The socket has an established connection between a local
     application and a remote peer.

     CLOSE_WAIT:  The socket connection has been closed by the remote peer,
     and the system is waiting for the local application to close its half of
     the connection.

     LAST_ACK:	The socket connection has been closed by the remote peer, the
     local application has closed its half of the connection, and the system
     is waiting for the remote peer to acknowledge the close.

     FIN_WAIT_1:  The socket connection has been closed by the local
     application, the remote peer has not yet acknowledged the close, and the
     system is waiting for it to close its half of the connection.

     FIN_WAIT_2:  The socket connection has been closed by the local
     application, the remote peer has acknowledged the close, and the system
     is waiting for it to close its half of the connection.

     CLOSING:  The socket connection has been closed by the local application
     and the remote peer simultaneously, and the remote peer has not yet
     acknowledged the close attempt of the local application.

     TIME_WAIT:	 The socket connection has been closed by the local
     application, the remote peer has closed its half of the connection, and
     the system is waiting to be sure that the remote peer received the last
     acknowledgement.

     The interface display provides a table of cumulative statistics regarding
     packets transferred, errors, and collisions.  The network addresses of
     the interface and the maximum transmission unit (“mtu”) are also dis‐
     played.

     The routing table display indicates the available routes and their sta‐
     tus.  Each route consists of a destination host or network and a gateway
     to use in forwarding packets.  The flags field shows a collection of
     information about the route stored as binary choices.  The individual
     flags are discussed in more detail in the route(8) and route(4) manual
     pages.  The mapping between letters and flags is:

     1	     RTF_PROTO1	      Protocol specific routing flag #1
     2	     RTF_PROTO2	      Protocol specific routing flag #2
     3	     RTF_PROTO3	      Protocol specific routing flag #3
     B	     RTF_BLACKHOLE    Just discard packets (during updates)
     b	     RTF_BROADCAST    The route represents a broadcast address
     C	     RTF_CLONING      Generate new routes on use
     c	     RTF_PRCLONING    Protocol-specified generate new routes on use
     D	     RTF_DYNAMIC      Created dynamically (by redirect)
     G	     RTF_GATEWAY      Destination requires forwarding by intermediary
     H	     RTF_HOST	      Host entry (net otherwise)
     L	     RTF_LLINFO	      Valid protocol to link address translation
     M	     RTF_MODIFIED     Modified dynamically (by redirect)
     R	     RTF_REJECT	      Host or net unreachable
     S	     RTF_STATIC	      Manually added
     U	     RTF_UP	      Route usable
     W	     RTF_WASCLONED    Route was generated as a result of cloning
     X	     RTF_XRESOLVE     External daemon translates proto to link address

     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 pro‐
     vides a count of the number of packets sent using that route.  The inter‐
     face entry indicates the network interface utilized for the route.

     When netstat is invoked with the -w option and a wait interval argument,
     it displays a running count of statistics related to network interfaces.
     An obsolete version of this option used a numeric parameter with no
     option, and is currently supported for backward compatibility.  By
     default, this display summarizes information for all interfaces.  Infor‐
     mation for a specific interface may be displayed with the -I option.

SEE ALSO
     fstat(1), nfsstat(1), ps(1), sockstat(1), inet(4), unix(4), hosts(5),
     networks(5), protocols(5), services(5), iostat(8), trpt(8), vmstat(8)

HISTORY
     The netstat command appeared in 4.2BSD.

     IPv6 support was added by WIDE/KAME project.

FILES
     /kernel	default kernel namelist
     /dev/kmem	default memory file

BUGS
     The notion of errors is ill-defined.

Darwin				 June 15, 2001				Darwin
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