netstat

netstat - Display statistics related to networking.

 netstat(1)                                                       netstat(1) NAME      netstat - show network status SYNOPSIS      netstat [-aAn] [-f address-family] [system [core]]      netstat [-mMnrsv] [-f address-family] [-p protocol] [system [core]]      netstat [-gin] [-I interface] [interval] [system [core]] DESCRIPTION      netstat displays statistics for network interfaces and protocols, as      well as the contents of various network-related data structures.  The      output format varies according to the options selected.  Some options      are ignored when used in combination with other options.      Generally, the netstat command takes one of the three forms shown      above:           -  The first form of the command displays a list of active              sockets for each protocol.           -  The second form displays the contents of one of the other              network data structures according to the option selected.           -  The third form displays configuration information for each              network interface.  It also displays network traffic data on              configured network interfaces, optionally updated at each              interval, measured in seconds. Options are interpreted as follows:           -a                Show the state of all sockets, including                             passive sockets used by server processes.  When                             netstat is used without any options (except -A                             and -n), only active sockets are shown.  This                             option does not show the state of X.25                             programmatic access sockets.  The option is                             ignored if the -g, -i, -I, -m, -M, -p, -r, -s                             or interval option is specified.           -A                Show the address of the protocol control block                             associated with sockets.  This option is used                             for debugging.  It does not show the X.25                             programmatic access control blocks.  This                             option is ignored if the -g, -i, -I, -m, -M,                             -p, -r, -s or interval option is specified.           -f address-family Show statistics or address control block for                             only the specified address-family.  The                             following address families are recognized: inet                             for AF_INET, and unix for AF_UNIX.  This option                             applies to the -a, -A and -s options.           -g                Show multicast information for network                             interfaces.  Only the address family AF_INET is                             recognized by this option.  This option may be                             combined with the -i option to display both                             kinds of information.  The option is ignored if                             the -m, -M or -p option is specified.           -i                Show the state of network interfaces.                             Interfaces that are statically configured into                             a system, but not located at boot time, are not                             shown.  This option is ignored if the -m, -M or                             -p option is specified.           -I interface      Show information about the specified interface                             only.  This option applies to the -g and -i                             options.           -m                Show statistics recorded by network memory                             management routines.  If this option is                             specified, all other options are ignored.           -M                Show the multicast routing tables.  When -s is                             used with the -M option, netstat displays                             multicast routing statistics instead.  This                             option is ignored if the -m or -p option is                             specified.           -n                Show network addresses as numbers.  Normally,                             netstat interprets addresses and attempts to                             display them symbolically.  This option applies                             to the -a, -A, -i, -r and -v options.           -p protocol       Show statistics for the specified protocol.                             The following protocols are recognized: tcp,                             udp, ip, icmp, igmp, arp, and probe.  This                             option is ignored if the -m option is                             specified.           -r                Show the routing tables.  When -v is used with                             the -r option, netstat also displays the                             network masks in the route entries.  When -s is                             used with the -r option, netstat displays                             routing statistics instead.  This option is                             ignored if the -g, -m, -M, -i, -I, -p or                             interval option is specified.           -s                Show statistics for all protocols.  When this                             option is used with the -r option, netstat                             displays routing statistics instead.  When this                             option is used with the -M option, netstat                             displays multicast routing statistics instead.                             This option is ignored if the -g, -i, -I, -m,                             -p or interval option is specified.           -v                Show additional routing information.  When -v                             is used with the -r option, netstat also                             displays the network masks in the route                             entries.  This option only applies to the -r                             option.      The arguments system and core allow substitutes for the defaults,      /stand/vmunix and /dev/kmem.      If no options or only the -A or -n option is specified, netstat      displays the status of only active sockets.  The display of active and      passive sockets status 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 the host portion of a socket address is zero.  When      known, the host and network addresses are displayed symbolically by      using gethostbyname() and getnetbyname(), respectively (see      gethostbyname(3N) and getnetbyname(3N)).  If a symbolic name for an      address is unknown, or if the -n option is specified, the address is      displayed 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 an asterisk      (*).      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 displayed.  When the interval argument is specified, netstat      displays a running count of statistics related to network interfaces.      This display consists of a column for the primary interface (the first      interface found during auto-configuration) and a column summarizing      information for all interfaces.  To replace the primary interface with      another interface, use 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.      The routing table display indicates the available routes and their      status.  Each route consists of a destination host or network, a      netmask and a gateway to use in forwarding packets.  The Flags field      shows whether the route is up (U), whether the route is to a gateway      (G), whether the route is a host or network route (with or without H),      whether the route was created dynamically (D) by a redirect or by Path      MTU Discovery, and whether a gateway route has been modified (M), or      it has been marked doubtful (?) due to the lack of a timely ARP      response.      The Netmask field shows the mask to be applied to the destination IP      address of an IP packet to be forwarded. The result will be compared      with the destination address in the route entry. If they are the same,      then the route is one of the candidates for routing this IP packet.      If there are several candidate routes, then the route with the longest      Netmask field (contiguous 1's starting from the leftmost bit position)      will be chosen. (see routing (7).)      The Gateway field shows the address of the immediate gateway for      reaching the destination. It can be the address of the outgoing      interface if the destination is on a directly connected network.      The Refs field shows 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 normally      obtain a route just while sending a particular message.  The Use field      shows a count of the number of packets sent using the route.  The      Interface field identifies which network interface is used for the      route.      The Pmtu and PmtuTime fields apply only to host routes.  The Pmtu      field for network and default routes is the same as the MTU of the      network interface used for the route.  If the route is created with a      static PMTU value (see route(1M)), the corresponding PmtuTime field      contains the word perm, and the PMTU value permanently overrides the      interface MTU.  If the route is created dynamically (D in the Flags      field), the value in the corresponding PmtuTime field is the number of      minutes remaining before the PMTU expires.  When the PMTU expires, the      system rediscovers the current PMTU for the route, in case it has      changed.  The PmtuTime field is left blank when the PMTU is identical      to the MTU of the interface. An asterisk (*) in the Pmtu field      indicates that user has disabled the PMTU Discovery for the route. DEPENDENCIES    X.25:      -A and -a options do not list X.25 programmatic access information. AUTHOR      netstat was developed by the University of California, Berkeley. SEE ALSO      hosts(4), networks(4), gethostbyname(3N), getnetbyname(3N),      protocols(4), route(1M), services(4).