What is ip2as

ip2as is a small perl module to help map IP adresses to ASN. Both IP version are supported transparently.

Prerequisites

• Perl (5.14 required)
• libnet-patricia-perl
• libjson-xs-perl (optional, you should use it)

How to use

• First, create a json with a list of prefix -> ASN. tools/ip2asn.json is provided full a snapshot of the current internet view.
• Load the json:

ip2as::init('path/to/mapping.json');

• Do some queries:

print ip2as::getas4ip('8.8.8.8'); #prints 15169
print ip2as::getas4ip('2001:4f8:1:10:0:1991:8:25'); #prints 1280

• When nothing is found, getas4ip returns undef.

Known bugs

This is not really a code-bug, but the default file contains stupid data due to misinformation from the RIPE (and some bad folks):

print ip2as::getas4ip('::') . "\n"; #prints 29049
print ip2as::getas4ip('10.0.0.1') . "\n"; #prints 15576

That specific issue is now fixed (by static exclusion), it remains sensitive to bad data.