ifconfig(1M) TCP/IP 5.4R3.00 ifconfig(1M)
NAME
ifconfig - configure DG/UX System network interface
SYNOPSIS
ifconfig interface [ address [netmask mask ] [ broadcast baddr ] ] [
metric n ] [ dstaddr daddr ] [ addrmaskreply on | off ] [ start |
stop ]
where:
interface A string that specifies the name and unit number of the
network interface, such as inen0
address A name found in the host database (/etc/hosts) or an
Internet address expressed in the Internet standard dot
notation
mask A 32-bit number that identifies which bits of the host's
Internet address indicate the subnet number
baddr An IP broadcast address
n An integer greater than or equal to 0
daddr The address of the other end of a point-to-point connection
DESCRIPTION
The ifconfig command controls a network interface for the TCP/IP
protocol stack. It assigns an address to a network interface,
configures the network interface parameters, and stops and restarts
message passing for that interface. You must use ifconfig when you
bring an interface up to define its network address; you can also use
it later to redefine an interface address.
If you omit the optional arguments, ifconfig displays the current
configuration for the specified network interface.
Use the netmask option with address assignment to specify a network
mask to use for subnetting. The broadcast option, which you also can
use with address assignment, changes the IP broadcast address for the
given interface to the specified value. You can change the interface
address, the broadcast address, and the netmask mask only if the
interface is stopped.
Routing protocols such as routed(1M) use the metric option to
determine the relative cost of using a particular link.
The dstaddr argument specifies the address of the other end of a
point-to-point connection.
The addrmaskreply argument is a switch that permits the interface to
generate replies to ICMP Address Mask Request messages if it is on or
prevents replies if turned off. The switch is on by default.
The key words start|stop represent the following:
start: Enables sending and receiving messages.
stop: Disables sending and receiving messages.
If the interface is capable of broadcasting and the broadcast command
line option is not supplied, ifconfig uses the default broadcast
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address for the interface. If the netmask command line option is not
supplied, the default network mask for the address is used. The
default will disable subnetting at the interface.
Only the superuser can change the configuration of a network
interface.
EXAMPLES
ifconfig inen0 128.0.0.31
ifconfig inen0 hostB broadcast 128.0.0.0
ifconfig inen0 128.5.1.31 broadcast 128.5.1.0 netmask 0xffffff00
The first example assigns Internet address 128.0.0.31 to interface
inen0 with the default broadcast address. The second example maps
hostname hostB to an Internet address given in /etc/hosts and
associates that address with interface inen0. It also sets the IP
broadcast address to be 128.0.0.0. The third example assigns the
Internet address 128.5.1.31 to the interface inen0, sets the network
mask to 0xffffff00 so that the high-order 24 bits of the address will
be used as the Internet network number (network 128.5, subnet 1), and
sets the broadcast address so that its host number part is all
zeroes.
DIAGNOSTICS
The system displays messages when the specified interface does not
exist, when the requested address is unknown, when the user invoking
ifconfig is not the superuser, and when the broadcast value is not
satisfactory. For example, the only acceptable broadcast values for
unsubnetted class B addresses are as follows:
255.255.255.255
0.0.0.0
net-number.255.255
net-number.0.0
Though the first two broadcast values are valid, they specify to
broadcast to all nodes in the Internet, so very few people would find
them acceptable. To broadcast to a given network, specify the net-
number (for example, 128.223) in the network portion of the broadcast
address, and either all 0's or all 1's (255.255) in the host portion.
0's are BSD 4.2 compatible; 1's are BSD 4.3 compatible.
Flags
The following flags (listed in the order of their bit positions) may
be present:
UP Interface is STARTED and RUNNING
BROADCAST Interface has capability to broadcast (some
interfaces, such as loop, do not support broadcasting)
IFFPOINTOPOINT
Interface is associated with a network device that
provides a point-to-point link.
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LOOPBACK Interface is associated with a loopback network. This
flag is present only for the loop interface.
RUNNING LAN controller is working. It was activated either by
the netinit(1M) command or by another protocol stack
using the same LAN controller.
NOARP Interface does not support the address resolution
protocol. Interfaces without BROADCAST capability
always have this flag present.
STARTED Interface enabled for sending and receiving data. It
is adjusted with ifconfig start|stop
NOADDRMASKREPLY
Interface will not generate replies to ICMP Address
Mask Request messages.
SEE ALSO
netinit(1M), routed(1M).
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