IFCONFIG(1M) IFCONFIG(1M)
NAME
ifconfig - configure network interface parameters
SYOPNSIS
/etc/ifconfig interface address_family [ address [
dest_address ] ] [ parameters ]
/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(4), 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.
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IFCONFIG(1M) IFCONFIG(1M)
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(7P); 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(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;
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
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IFCONFIG(1M) IFCONFIG(1M)
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 ALSO
netstat(1), intro(7N), rc(1M)
ORIGIN
4.3 BSD
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