Complete List of Class A and Class B Networks

This list is not unique–there are other lists of Internet IP networks on the Web (1), but this
particular list has the advantage that it is reasonably current, includes both Class A and Class B networks, has
contact information on the various networks, and also offers a downloadable list suitable for further data analysis.

Now, this information is of course readily available through the whois service at the three regional Internet
registries (ARIN, RIPE, and
APNIC), but this does not allow you to perform, say, statistical analysis on the data,
as records are retrieved one-at-a-time.

To get an overall view of the IPv4 address space, I went ahead and compiled a list of all Class A and Class B networks
for the enjoyment of the interested public. This list was compiled by querying the ARIN database for all Class A- and Class B records,
with additional information taken from RIPE and APNIC if a corresponding reference was returned by ARIN.

The data was then put into a form suitable to be displayed in a table using custom built Perl scripts. The data
was retrieved from the registry databases on Sept 3, 1999, and the final version of the Network Tables was uploaded
onto this server on Sept 19, 1999.

For simplicity, we assume the classic subdivision into A, B, etc. network classes. No effort was made to accomodate
more recent developments, such as CIDR (Classless Inter-Domain Routing).

Feedback and suggestions are highly encouraged. Please contact me at [email protected].

(1): See for instance http://www.apnic.net/db/RIRs.html.
This site also presents a conceptual overview of the complete IPv4 address space.
Dragonstar has a list that includes Classes A, B and C, but is
not always current, and some ranges are better covered than others.

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