ifconfig(1M) ifconfig(1M)NAME ifconfig - configure network interface parameters SYNOPSIS /etc/ifconfig interface [address [dest-address]] [parameter...] /etc/ifconfig interface [protocol-family] DESCRIPTION ifconfig is used to assign an address to a network interface or configure network interface parameters. ifconfig must be used at boot time to define the network address of each in- terface present on a machine; it may also be used at a later time to redefine an interface's address or other operating parameters. The interface parameter is a string of the form name unit, for example, ae0. A DARPA-Internet address is either a host name present in the host name data base, hosts(4), or a DARPA Internet ad- dress expressed in the Internet standard ``dot notation.'' The following parameters may be set with ifconfig: 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 reinitial- ized. down Mark an interface ``down.'' When an inter- face is marked ``down,'' the system does not attempt to transmit messages through that in- terface. If possible, the interface is reset to disable reception as well. This action does not automatically disable routes using the interface. trailers Request the use of a ``trailer'' link level encapsulation when sending (default). If a network interface supports trailers, the sys- tem will, when possible, encapsulate outgoing messages in a manner which minimizes the number of memory to memory copy operations performed by the receiver. On networks that support the Address Resolution Protocol (see arp(5P); currently, only 10 Mb/s Ethernet), this flag indicates that the system should request that other systems use trailers when sending to this host. Similarly, trailer en- April, 1990 1
ifconfig(1M) ifconfig(1M)capsulations will be sent to other hosts that have made such requests. Currently used by Internet protocols only. -trailers Disable the use of a ``trailer'' link level encapsulation. arp Enable the use of the Address Resolution Pro- tocol in mapping between network level ad- dresses 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, (the default is 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. debug Enable driver dependent debugging code; usu- ally, this turns on extra console error log- ging. -debug Disable driver dependent debugging code. netmask mask (Inet only) Specify how much of the address to reserve for subdividing networks into sub- networks. The mask includes the network part of the local address and the subnet part, which is taken from the host field of the ad- dress. The mask can be specified as a single hexadecimal number with a leading 0x, with a dot-notation Internet address, or with a pseudo-network name listed in the network table networks(4N). The mask contains 1's for the bit positions in the 32-bit address which are to be used for the network and sub- net parts, and 0's for the host part. The mask should contain at least the standard network portion, and the subnet field should be contiguous with the network portion. dstaddr Specify the address of the correspondent on the other end of a point-to-point link. broadcast (Inet only) Specify the address to use to 2 April, 1990
ifconfig(1M) ifconfig(1M)represent broadcasts to the network. The de- fault broadcast address is the address with a host part of all 1's. ifconfig displays the current configuration for a network interface when no optional parameters are supplied. If a protocol family is specified, ifconfig will report only the details specific to that protocol family. Only the superuser may modify the configuration of a network interface. DIAGNOSTICS Messages indicating the specified interface does not exit, the requested address is unknown, or the user is not privileged and tried to alter an interface's configuration. FILES /etc/ifconfig SEE ALSO netstat(1), rc(1M), intro(5). April, 1990 3