HP-UX 11i September 2001 Release Notes
Internet and Networking Services
Network Transport (new at 11i original release)
Chapter 10
158
Network Transport (new at 11i original release)
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
To disallow subnet fields with all ones or all zeroes, set the ndd parameter
ip_check_subnet_addr to 1 in the nddconf file.
ndd
ndd is a networking configuration tool used to customize the networking kernel. To make
an 11i system more Internet friendly and easier to run “out of the box”, some of the ndd
tunable parameters defaults changed. Some unsupportable tunable parameters are now
“supported”. Also, some new tunable parameters have been added. Some of the changes
reflect changes to the networking industry standards.
Specific Changes
1) All 1’s or all 0’s now allowed in masked bits of subnet address: