ifconfig(1M)                 UNIX System V(TCP/IP)                 ifconfig(1M)


NAME
      ifconfig - configure network interface parameters

SYNOPSIS
      ifconfig interface [ address_family ] [ address [ dest_address ] ] [
      parameters ]
                   [ broadcast address ] [ metric n ]

      ifconfig interface [ protocol_family ]

DESCRIPTION
      ifconfig is used to assign an address to a network interface and/or to
      configure network interface parameters.  ifconfig must be used at boot
      time to define the network address of each interface present on a
      machine; it may also be used at a later time to redefine an interface's
      address or other operating parameters.  Used without options, ifconfig
      displays the current configuration for a network interface.  If a
      protocol family is specified, ifconfig will report only the details
      specific to that protocol family.  Only the super-user may modify the
      configuration of a network interface.

      The interface parameter is a string of the form name unit, for example
      emd1.

      Since an interface may receive transmissions in differing protocols, each
      of which may require separate naming schemes, the parameters and
      addresses are interpreted according to the rules of some address family,
      specified by the address_family parameter.  The address families
      currently supported are ether and inet.  If no address family is
      specified, inet is assumed.

      For the DARPA Internet family (inet), the address is either a host name
      present in the host name data base [see hosts(4)], or a DARPA Internet
      address expressed in the Internet standard dot notation.  Typically, an
      Internet address specified in dot notation will consist of your system's
      network number and the machine's unique host number.  A typical Internet
      address is 192.9.200.44, where 192.9.200 is the network number and 44 is
      the machine's host number.

      For the ether address family, the address is an Ethernet address
      represented as x:x:x:x:x:x where x is a hexadecimal number between 0 and
      ff.  Only the super-user may use the ether address family.

      If the dest_address parameter is supplied in addition to the address
      parameter, it specifies the address of the correspondent on the other end
      of a point to point link.

OPTIONS
      The following parameters may be set with ifconfig:





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ifconfig(1M)                 UNIX System V(TCP/IP)                 ifconfig(1M)


     up     Mark an interface up.  This may be used to enable an interface
             after an ifconfig down.  It happens automatically when setting the
             first address on an interface.  If the interface was reset when
             previously marked down, the hardware will be re-initialized.

     down   Mark an interface down.  When an interface is marked down, the
             system will not attempt to transmit messages through that
             interface.  If possible, the interface will be reset to disable
             reception as
             well.  This action does not automatically disable routes using the
             interface.

     trailers
             (inet only) Enable the use of a trailer link level encapsulation
             when sending.  If a network interface supports trailer
             encapsulation, the system will, when possible, encapsulate
             outgoing messages in a manner which minimizes the number of memory
             to memory copy operations performed by the receiver.  This feature
             is machine-dependent, and therefore not recommended.  On networks
             that support the Address Resolution Protocol [see arp(7)];
             currently, only 10 Mb/s Ethernet), this flag indicates that the
             system should request that other systems use trailer encapsulation
             when sending to this host.  Similarly, trailer encapsulations will
             be used when sending to other hosts that have made such requests.

     -trailers
             Disable the use of a trailer link level encapsulation.

     arp    Enable the use of the Address Resolution Protocol in mapping
             between network level addresses and link level addresses
             (default).  This is currently implemented for mapping between
             DARPA Internet addresses and 10Mb/s Ethernet addresses.

     -arp   Disable the use of the Address Resolution Protocol.

     metric n
             Set the routing metric of the interface to n, default 0.  The
             routing metric is used by the routing protocol [routed(1M)].
             Higher metrics have the effect of making a route less favorable;
             metrics are counted as addition hops to the destination network or
             host.

     broadcast address
             (inet only) Specify the address to use to represent broadcasts to
             the network.  The default broadcast address is the address with a
             host part of all 1's.  A + (plus sign) given for the broadcast
             value causes the broadcast address to be reset to a default
             appropriate for the (possibly new) Internet address.

EXAMPLES




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ifconfig(1M)                 UNIX System V(TCP/IP)                 ifconfig(1M)


      If your workstation is not attached to an Ethernet, the emd1 interface
      should be marked down as follows:

            ifconfig emd1 down

FILES
      /dev/nit

SEE ALSO
      netstat(1M),

DIAGNOSTICS
      Messages indicating the specified interface does not exist, the requested
      address is unknown, or the user is not privileged and tried to alter an
      interface's configuration.







































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