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

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[править] NAME

    netstat -- show network status

[править] 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.
    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 sec-
            ond 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 ses-
            sions.  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 symboli-
          cally.
    -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 net-
    work 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 numeri-
    cally, 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 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 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 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 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.  Infor-
    mation 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 repre-
    sented 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 auto-
         matically
    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.

[править] 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)

[править] HISTORY

    The netstat command appeared in 4.2BSD.
    IPv6 support was added by WIDE/KAME project.

[править] BUGS

    The notion of errors is ill-defined.

FreeBSD 9.0 February 22, 2010 FreeBSD 9.0