HP-UX Reference (11i v2 04/09) - 1M System Administration Commands A-M (vol 3)

i
ifconfig(1M) ifconfig(1M)
be enabled for Address Resolution Protocol.
-arp (inet only) Disable the use of the Address Resolution Protocol. If
an interface already had the Address Resolution Protocol enabled,
the user must "unplumb" the interface before it can be disabled for
Address Resolution Protocol.
plumb Setup the Streams plumbing needed for TCP/IP for a primary
interface name. (See the Interface Naming subsection given
below.). By default, the plumb operation is done automatically
when an IP address is specified for an interface.
unplumb Tear down the Streams plumbing for a primary interface name.
(See the Interface Naming subsection given below.) Secondary
interface does not require "plumbing". A secondary IPv4 interface
can be removed by assigning an IP address of 0.0.0.0 to it.
Remove a secondary IPv6 interface by assigning an IP address of ::
to it.
Interface Naming
The interface name associated with a network card is composed of the name of the interface (e.g.
lan or
snap ), the ppa number which identifies the card instance for this interface, and an optional IP index
number which allows the configuration of multiple IP addresses for an interface. For LAN cards, the
interface name
lan will be used to designate Ethernet encapsulation and
snap for IEEE 802.3 encapsu-
lation. The
lanscan command can be used to display the interface name and ppa number of each inter-
face that is associated with a network card (see lanscan (1M)).
IPv4 and IPv6 interfaces can coexist over the same physical network interface device using the same
naming scheme. IPv6 interfaces are configured using the "inet6" ifconfig subcommand. (See the IPv6
subsection given below.)
The tunnel interface names should be
iptu* for "IP6-in-IP" tunnels and 6to4 tunnels. Example:
iptu0, iptu1. The tunnel interface names should be ip6tu* for "IP-in-IP6" tunnels and "IP6-in-IP6"
tunnels. Example: ip6tu0, ip6tu1.
IP Index Number
Multiple IP addresses assigned to the same interface may be in different subnets. An example of an inter-
face name without an IP index number is
lan0. An example of an interface name with a IP index
number is
lan0:1. Note: specifying lan0:0 is equivalent to lan0.
A primary interface is an interface whose IP index number is zero. A secondary interface is an interface
whose IP index number is non-zero.
Loopback Interface
The loopback interface (
lo0) is automatically configured when the system boots with the TCP/IP
software. The IP address and netmask of the primary IPv4 loopback interface are 127.0.0.1 and
255.0.0.0, respectively. The IP address and prefix of the primary IPv6 loopback interface are ::1 and 128
respectively. The user is not permitted to change the address of the primary loopback interface (lo0:0).
It is permissible to assign other IP addresses to lo0 with non-zero IP index numbers (lo0:1, lo0:2, etc).
This allows a system to have a "system IP" address that is available as long as one interface remains
usable.
Supernets
(inet only) A supernet is a collection of smaller networks. Supernetting is a technique of using the net-
mask to aggregate a collection of smaller networks into a supernet.
This technique is particularly useful when the limit of 254 hosts per class C network is too restrictive. In
those situations a netmask containing only a portion of the network part may be applied to the hosts in
these networks to form a supernet. This supernet netmask should be applied to those interfaces that con-
nect to the supernet using the ifconfig command. For example, a host can configure its interface to con-
nect to a class C supernet, 192.6, by configuring an IP address of 192.6.1.1 and a netmask of 255.255.0.0
to its interface.
HP-UX 11i Version 2: September 2004 − 3 − Hewlett-Packard Company Section 1M−−301