This is a MIRROR. Please note, that the data itself is from 1997 and is not maintained in any way.
An index relating IP network numbers to network names and identities, for class A, B and C networks


(0.x.x.x to 127.x.x.x)


(128.0.x.x to 191.255.x.x)


(192.0.0.x to 223.255.255.x)

The IP Network Numbering System
The present system of IP network numbers, established in 1981, uses a 32 bit number to identify computers on the internet. These numbers are represented as a sequence of four 8 bit numbers (octets), each of which can therefore vary between 0 and 255. The first part of each 32 bit number represents the network, and the remaining part refers to the individual computer.
To accommodate different network sizes, IP address space was originally divided into three sections; Class A (0.x.x.x to 127.x.x.x) - 8 bit network prefix, Class B (128.0.x.x to 191.255.x.x) - 16 bit network prefix and Class C (192.0.0.x to 223.255.255.x) - 24 bit network prefix. These classes remain generally applicable, but the introduction of Classless Inter-Domain Routing (CIDR) has allowed for the more efficient division of address space to create arbitrary sized networks.

The list is extracted from the whois database at the Internic. As of December 22, 1997, control of IP network allocation has passed to Arin (American Register of Internet Networks). There are similar organisations for European (www.ripe.net) and Asian-Pacific (www.apnic.net) networks.

For more details about individual networks, use the arin whois service

Please read the FAQ