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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.  The flags field shows available ISR
             handlers:

             C        NETISR_SNP_FLAGS_M2CPUID           Able to map mbuf to
                                                         cpu id
             D        NETISR_SNP_FLAGS_DRAINEDCPU        Has queue drain
                                                         handler
             F        NETISR_SNP_FLAGS_M2FLOW            Able to map mbuf to
                                                         flow id

             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         March 10, 2013         FreeBSD 11.0-PRERELEASE

NAME | DESCRIPTION | SEE ALSO | HISTORY | BUGS

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