CC2ASN is a simple lookup service for AS-numbers and prefixes belonging to any given country in the world. Note that this is not a geolocation service, where you lookup IPs to get geo-data back. Using CC2ASN you lookup a country and get all associated ASNs and prefixes (both v4 and v6) back.
ASN - an autonomous system (AS) is a collection of connected IP routing prefixes under mutual administration, usually by a single organization or entity. In most cases the AS-number refers to either an ISP (Internet Service Provider) or a corporation/organization. The AS-number is an integer of either 16-bit or 32-bit, and can be written as either a simple numeric form (asplain) or in a dotted format (asdot). As with IP allocations, AS assigments also have reservations with a certain special meaning. Read more
Prefix - Subdivision of an internet protocol (IP) network, where the routing prefix is expressed in CIDR-notation, where it is written as the first address of a network, followed by a slash character (/), and ending with the bit-length of the prefix (e.g. 192.168.0.1/24). As in IPv4, subnetting in IPv6 is based on the concepts of variable-length subnet masking (VLSM) and the Classless Inter-Domain Routing (CIDR) methodology. Read more
CC - a country code (CC) is a unique numeric representation for a given country. This services uses the ISO 3166-1 Alpha-2 standard codes, which uses a two-letter code as defined by the International Organization for Standardization (ISO) to represent countries, dependent territories, and special areas of geographical interest. Examples are; NO for Norway, SJ for Svalbard and Jan Mayen (even though they are Norwegian territories) and PS for Palestine. Read more
All the data is based on publicly available information from the five RIRs (Regional Internet Registry) in the world; ARIN, RIPE NCC, APNIC, LACNIC and AFRINIC. Each RIR publish a delegation file using the Statistics Exchange Format (SEF). The delegation files are updated once every day. CC2ASN parses these files and restructure the data, based on country code. The data is then made available through an API and a legacy whois-server.
The details of the SEF definition are to be considered a published RIR standard, on which other parties are expected to rely. RIRs must comply with this standard in every respect.
The RIRs state that even though this data indicates the country where resources were first allocated or assigned, it was never intended that the data be considered as an authoritative statement of the location where any specific resource may currently be in use.
So, what exactly can this all be used for? Well there are multiple applications for these data, and I do not claim to know them all. One of the reasons I created the CC2ASN service, was a need to classify and filter network flows for a given country based on AS-numbers alone, as part of doing netflow analysis work. And it was easier to process smaller sets of AS-numbers, rather than big IP sets. In addition the network flows contained and was indexed on ASNs among other things.
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