IFCONFIG(8C)IFCONFIG(8C)NAMEifconfig - configure network interface parameters
SYNOPSIS
/usr/etc/ifconfig interface address_family [ address [ dest_address ] ]
[ parameters ]
/usr/etc/ifconfig interface [ protocol_family ]
DESCRIPTION
Ifconfig is used to assign an address to a network interface and/or
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. The interface parameter is a
string of the form ``name unit'', e.g. ``en0''.
Since an interface may receive transmissions in differing protocols,
each of which may require separate naming schemes, it is necessary to
specify the address_family, which may change the interpretation of the
remaining parameters. The address families currently supported are
``inet'' and ``ns''.
For the DARPA-Internet family, the address is either a host name
present in the host name data base, hosts(5), or a DARPA Internet
address expressed in the Internet standard ``dot notation''. For the
Xerox Network Systems(tm) family, addresses are net:a.b.c.d.e.f, where
net is the assigned network number (in decimal), and each of the six
bytes of the host number, a through f, are specified in hexadecimal.
The host number may be omitted on 10Mb/s Ethernet interfaces, which use
the hardware physical address, and on interfaces other than the first.
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 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 Request the use of a ``trailer'' link level
encapsulation when sending (default). If a network
interface supports trailers, 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. On networks that
support the Address Resolution Protocol (see arp(4P);
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
encapsulations 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 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(8c)). 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; usually, this
turns on extra console error logging.
-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
address. 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(5). The mask
contains 1's for the bit positions in the 32-bit address
which are to be used for the network and subnet 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 represent
broadcasts to the network. The default broadcast
address is the address with a host part of all 1's.
ipdst (NS only) This is used to specify an Internet host who
is willing to receive ip packets encapsulating NS
packets bound for a remote network. In this case, an
apparent point to point link is constructed, and the
address specified will be taken as the NS address and
network of the destinee.
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 super-user 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.
SEE ALSOnetstat(1), intro(4N), rc(8)4.2 Berkeley Distribution May 22, 1986 IFCONFIG(8C)
