ifconfig(8c)															      ifconfig(8c)

Name
       ifconfig - configure network interface parameters

Syntax
       /etc/ifconfig interface [ address [ dest_address ] ] [ parameters ]

Description
       The  command assigns an address to a network interface and/or configures network interface parameters.  You must use at boot time to define
       the network address of each interface present on a machine. You can also use it at a later time to redefine an  interface's  address.   The
       interface parameter is a string of the form: name, unit, for example, en0.  The address is either a host name present in the host name data
       base, or a DARPA Internet address expressed in the Internet standard dot notation.

Arguments
       You can set the following parameters with

       up	 Marks an interface up.

       down	 Marks an interface down.  When an interface is marked down, the system does not attempt to transmit messages through that  inter-
		 face.

       trailers  Enables  the  use of a trailer link level encapsulation when sending.	If a network interface supports trailers, the system, when
		 possible, encapsulates outgoing messages in a manner that minimizes the number of memory-to-memory copy operations  performed	by
		 the receiver.
		 Although trailers is the default on some network interfaces, the use of trailers is not recommended; failures in trailer negotia-
		 tion can disrupt network transmissions.  See -trailers.

       -trailers Disables the use of a trailer link level encapsulation.  This is the recommended setting.

       promisc	 Enables the use of the in the promiscuous mode. The promiscuous mode allows the network interface to receive all the packets  off
		 the wire and pass it onto to the packet filter.

       -promisc  Disables the promiscuous mode of the packet filter. This is the default.

       +copyall  Sets  the interface into copy-all mode (receives packets sent/received by the kernel-resident protocol software [for example, IP,
		 ARP, DECnet, LAT] on this host).

       -copyall  Disables copy-all mode. (See for more information aboutut the flag.)

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

       -arp	 Disables the use of the Address Resolution Protocol.

       debug	 Enables driver-dependent debugging code. Usually, this turns on extra console error logging.

       -debug	 Disables driver dependent debugging code.

       netmask	 Specifies  how  many  bits  of  the  address you wish to reserve for subdividing Class A and B networks into sub-networks.  (Inet
		 only).

       dstaddr	 Specifies the correspondent on the other end of a point to point link.

       broadcast Specifies the address you wish to use to represent broadcasts to the network.

       The command displays the current configuration for a network interface when no optional parameters are supplied.

       Only the superuser can modify the configuration of a network interface.

Diagnostics
       The command returns messages indicating the specified interface does not exist, the requested address is unknown, the user tried  to  alter
       an interface's configuration but is not privileged.

See Also
       netstat(1), intro(4n), packetfilter(4), MAKEDEV(8), pfconfig(8c), pfstat(8), rc(8)

																      ifconfig(8c)