ifconfig

configure network interface parameters

Syntax:



ifconfig interface  [address [dest_address]] [parameters]

Options:

interface
A string of the form name unit (e.g. en1)
address
This is either a hostname present in the hosts database or a DARPA-Internet address expressed in the standard Internet ``dot notation.''
dest_address
The address of the correspondent on the other end of a point-to-point link (for slx and pppx interfaces only).
parameters
See below.

Description:

The ifconfig utility must be run to define the network address of each interface present on a machine; it may also be run later on to redefine an interface's address or to configure other interface parameters.

When no optional parameters are supplied, ifconfig displays the current configuration for a network interface. Only the superuser may modify the configuration of a network interface.

Here are the interface types supported at the time of printing:

enx
Ethernet
fddix
FDDI
lo0
loopback
pppx
PPP
slx
SLIP
trx
Token Ring

where x is the number of logical QNX LANs running the selected hardware protocol.

Parameters

With ifconfig, you may set the following parameters:

alias address
Establish an additional network address for this interface. You'll often find this useful when you're changing network numbers and wish to accept packets addressed to the old interface.
-alias address
Remove the additional network address for this interface.
arp
Enable the use of the Address Resolution Protocol in mapping between network-level addresses and link-level addresses (default).
-arp
Disable the use of the Address Resolution Protocol.
broadcast address
Use this address to represent broadcasts to the network. The default broadcast address is the address with a host part of all 1's.
delete address
Remove this network address. You would use this if you incorrectly specified an alias, or if the alias were no longer needed.
down
Mark an interface ``down.'' When an interface is marked down, the system won't attempt to transmit messages through that interface. If possible, the interface will be reset to disable reception as well. This action doesn't automatically disable routes using the interface.
metric n
Set the routing metric of the interface to n> (default is 0). The routing metric is used by the routing protocol, routed. Higher metrics have the effect of making a route less favorable; metrics are counted as additional hops to the destination network or host.
netmask mask
Reserve this much of the address for subdividing networks into subnetworks. The mask:
trailers
Use a ``trailer'' link-level encapsulation when sending (default). If a network interface supports trailers, the system will encapsulate outgoing messages in a way that minimizes the number of memory-to-memory copy operations performed by the receiver. On networks that support the Address Resolution Protocol (see arp protocol; 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 trailer link-level encapsulation.
up
Mark an interface ``up.'' You can use this command to enable an interface after an ifconfig down. By default, an interface is marked as ``up'' the first time ifconfig is run to assign the interface an address.

Diagnostics

Depending on the error, the utility may display messages indicating that:

See also:

netstat, routed