HP-UX 11i Release Notes (December 2000)

Internet and Networking Services
Network Transport (new)
Chapter 10194
Network Transport (new)
Network Transport includes ifconfig, ndd, netstat, virtual IP
address, setsockopt, and t_optmgmt.
ifconfig
The ifconfig subnet mask default now allows all 1’s or all 0’s in the
masked part of the subnet field. This provides up to twice as many IP
addresses as before. The default behavior now allows more IP address
and subnet mask combinations. However, any addresses working before
will continue working without alteration.
The subnet field is that portion of an IP address that identifies the
subnet beyond the network portion of the address. For example, a class A
IP address used with the mask 255.192.0.0 (0xffc000000) has a two-bit
subnet field which is the 5th and 6th bits shown below:
11111111 11 000000 00000000 00000000
ifconfig can now assign the following IP address, and subnet mask to
an interface, although the subnet field (subnet portion of the address) is
all 1’s:
IP address: 15.192.1.1
Subnet mask: 255.192.0.0 (0xffc00000)
In binary:
00001111 11 000000 00000001 00000001
11111111 11 000000 00000000 00000000
ifconfig can now also assign the following IP address and subnet mask
to an interface, although the subnet field is all 0’s:
IP address: 15.1.1.1
Subnet mask: 255.192.0.0 (0xffc00000)
In binary:
00001111 00 000001 00000001 00000001
11111111 11 000000 00000000 00000000