ifconfig(1M) ifconfig(1M)
NAME
ifconfig - configure network interface parameters
SYNOPSIS
ifconfig -a [parameters | protocol_family]
ifconfig interface [parameters | protocol_family]
DESCRIPTION
The ifconfig command is used to assign an address to a network
interface and/or to configure network interface parameters.
Files
/dev/ip
Diagnostics
ifconfig generates 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.
USAGE
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.
ifconfig requires a valid network device (interface) or -a for
its first argument. When the -a argument is used, all
initialized network boards are selected. Used without
options, ifconfig displays a usage message. If a
protocol_family is specified (for example: inet), ifconfig
will report only the details specific to that protocol_family.
Only a privileged user may modify the configuration of a
network interface.
The interface parameter is a string of the form prefixunit,
for example lo0 or wd0. See interface(4) for more information
on the prefixunit parameter.
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 protocol family, specified by the
protocol_family parameter. The protocol family currently
supported is inet. If no protocol family is specified, inet
is assumed.
Copyright 1994 Novell, Inc. Page 1
ifconfig(1M) ifconfig(1M)
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.
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
-a This option affects all initialized network interfaces
on the system. When used by itself, the -a option
displays information for all of the network interfaces
installed on the system. When the -a option is used
with any of the valid ifconfig options, the change(s)
will be applied to all of the initialized interfaces.
Using -a with some parameters, such as up and down, is
useful if you want to bring all of the initialized
network interfaces up or down. However, you would not
want to use the -a option with broadcast address. This
would effectively set the broadcast parameter for all of
the initialized interfaces to the same address, and
cause unpredictable results.
Parameters
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 (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)],
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 [see routed(1M)].
Higher metrics have the effect of making a
route less favorable; metrics are counted
as additional 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.
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ifconfig(1M) ifconfig(1M)
dblevel level Set the level of debugging to level.
Interpretation of level is interface
specific. For a PPP interface, see the
description of the debug option on
ppphosts(4).
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(4). 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. For example, to
create a netmask that has an 8 bit host ID
portion for a Class B address, such as
157.2.123.100, use either of:
netmask 255.255.255.0
netmask 0xffffff00
dest_address Specify the address of the correspondent
on the other end of a point to point link.
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.
Examples
If your workstation is not attached to an Ethernet, the wd0
interface should be marked down as follows:
ifconfig wd0 down
REFERENCES
interface(4), netstat(1M)
Copyright 1994 Novell, Inc. Page 4