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NETSTAT(1)              FreeBSD General Commands Manual             NETSTAT(1)

NAME
     netstat - show network status

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 information presented.

     netstat [-AaLnSTWx] [-f protocol_family | -p protocol] [-M core]
             [-N system]
             Display a list of active sockets (protocol control blocks) for
             each network protocol, for a particular protocol_family, or for a
             single protocol.  If -A is also present, show the address of a
             protocol control block (PCB) associated with a socket; used for
             debugging.  If -a is also present, show the state of all sockets;
             normally sockets used by server processes are not shown.  If -L
             is also present, 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, and the third count is the maximum number of queued
             connections.  If -S is also present, show network addresses as
             numbers (as with -n) but show ports symbolically.  If -x is
             present, display socket buffer and tcp timer statistics for each
             internet socket.  When -T is present, display information from
             the TCP control block, including retransmits, out-of-order
             packets received, and zero-sized windows advertised.

     netstat -i | -I interface [-abdhnW] [-f address_family] [-M core]
             [-N system]
             Show the state of all network interfaces or a single interface
             which have been auto-configured (interfaces statically configured
             into a system, but not located at boot time are not shown).  An
             asterisk (``*'') after an interface name indicates that the
             interface is ``down''.  If -a is also present, multicast
             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 -b is also present, show the number of bytes
             in and out.  If -d is also present, show the number of dropped
             packets.  If -h is also present, print all counters in human
             readable form.  If -W is also present, print interface names
             using a wider field size.

     netstat -w wait [-I interface] [-d] [-M core] [-N system] [-q howmany]
             At intervals of wait seconds, display the information regarding
             packet traffic on all configured network interfaces or a single
             interface.  If -q is also present, exit after howmany outputs.
             If -d is also present, show the number of dropped packets.

     netstat -s [-s] [-z] [-f protocol_family | -p protocol] [-M core]
             [-N system]
             Display system-wide statistics for each network protocol, for a
             particular protocol_family, or for a single protocol.  If -s is
             repeated, counters with a value of zero are suppressed.  If -z is
             also present, reset statistic counters after displaying them.

     netstat -i | -I interface -s [-f protocol_family | -p protocol] [-M core]
             [-N system]
             Display per-interface statistics for each network protocol, for a
             particular protocol_family, or for a single protocol.

     netstat -m [-M core] [-N system]
             Show statistics recorded by the memory management routines
             (mbuf(9)).  The network manages a private pool of memory buffers.

     netstat -B [-z] [-I interface]
             Show statistics about bpf(4) peers.  This includes information
             like how many packets have been matched, dropped and received by
             the bpf device, also information about current buffer sizes and
             device states.

     netstat -r [-AanW] [-f address_family] [-M core] [-N system]
             Display the contents of all routing tables, or a routing table
             for a particular address_family.  If -A is also present, show the
             contents of the internal Patricia tree structures; used for
             debugging.  If -a is also present, show protocol-cloned routes
             (routes generated by an RTF_PRCLONING parent route); normally
             these routes are not shown.  When -W is also present, show the
             path MTU for each route, and print interface names with a wider
             field size.

     netstat -rs [-s] [-M core] [-N system]
             Display routing statistics.  If -s is repeated, counters with a
             value of zero are suppressed.

     netstat -g [-W] [-f address_family] [-M core] [-N system]
             Display the contents of the multicast virtual interface tables,
             and multicast forwarding caches.  Entries in these tables will
             appear only when the kernel is actively forwarding multicast
             sessions.  This option is applicable only to the inet and inet6
             address families.

     netstat -gs [-s] [-f address_family] [-M core] [-N system]
             Show multicast routing statistics.  If -s is repeated, counters
             with a value of zero are suppressed.

     netstat -Q
             Show netisr(9) statistics.

     Some options have the general meaning:

     -f address_family, -p protocol
           Limit display to those records of the specified address_family or a
           single protocol.  The following address families and protocols are
           recognized:

           Family                               Protocols
           inet (AF_INET)                       divert, icmp, igmp, ip, ipsec,
                                                pim, sctp, tcp, udp
           inet6 (AF_INET6)                     icmp6, ip6, ipsec6, rip6, tcp,
                                                udp
           pfkey (PF_KEY)                       pfkey
           atalk (AF_APPLETALK)                 ddp
           netgraph, ng (AF_NETGRAPH)           ctrl, data
           ipx (AF_IPX)                         ipx, spx
           unix (AF_UNIX)
           link (AF_LINK)

           The program will complain if protocol is unknown or if there is no
           statistics routine for it.

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

     -N    Extract the name list from the specified system instead of the
           default, which is the kernel image the system has booted from.

     -n    Show network addresses and ports as numbers.  Normally netstat
           attempts to resolve addresses and ports, and display them
           symbolically.

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

     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 databases hosts(5)
     and networks(5), 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 IPv4 ``dot format'', refer to inet(3).
     Unspecified, or ``wildcard'', addresses and ports appear as ``*''.

     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.

     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 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 pkts (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
     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 the -w option and a wait interval argument,
     it displays a running count of statistics related to network interfaces.
     An obsolescent 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.
     Information for a specific interface may be displayed with the -I option.

     The bpf(4) flags displayed when netstat is invoked with the -B option
     represent the underlying parameters of the bpf peer.  Each flag is
     represented as a single lower case letter.  The mapping between the
     letters and flags in order of appearance are:

     p        Set if listening promiscuously
     i        BIOCIMMEDIATE has been set on the device
     f        BIOCGHDRCMPLT status: source link addresses are being filled
              automatically
     s        BIOCGSEESENT status: see packets originating locally and
              remotely on the interface.
     a        Packet reception generates a signal
     l        BIOCLOCK status: descriptor has been locked

     For more information about these flags, please refer to bpf(4).

     The -x flag causes netstat to output all the information recorded about
     data stored in the socket buffers.  The fields are:

     R-MBUF        Number of mbufs in the receive queue.
     S-MBUF        Number of mbufs in the send queue.
     R-CLUS        Number of clusters, of any type, in the receive queue.
     S-CLUS        Number of clusters, of any type, in the send queue.
     R-HIWA        Receive buffer high water mark, in bytes.
     S-HIWA        Send buffer high water mark, in bytes.
     R-LOWA        Receive buffer low water mark, in bytes.
     S-LOWA        Send buffer low water mark, in bytes.
     R-BCNT        Receive buffer byte count.
     S-BCNT        Send buffer byte count.
     R-BMAX        Maximum bytes that can be used in the receive buffer.
     S-BMAX        Maximum bytes that can be used in the send buffer.

SEE ALSO
     fstat(1), nfsstat(1), procstat(1), ps(1), sockstat(1), bpf(4), inet(4),
     route(4), unix(4), hosts(5), networks(5), protocols(5), services(5),
     iostat(8), route(8), trpt(8), vmstat(8), mbuf(9)

HISTORY
     The netstat command appeared in 4.2BSD.

     IPv6 support was added by WIDE/KAME project.

BUGS
     The notion of errors is ill-defined.

FreeBSD 11.0-PRERELEASE        February 22, 2010       FreeBSD 11.0-PRERELEASE

NAME | DESCRIPTION | SEE ALSO | HISTORY | BUGS

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