ASN to IP Mapping

Geoff Huston gih at
Sun Mar 8 03:37:40 UTC 2015

> On 8 Mar 2015, at 1:39 pm, Randy Bush <randy at> wrote:
>> If you want to know the registry assignments / allocations made to a
>> single entity and be able group together these assignments of address
>> prefixes and ASNs you should retrieve the combined extended stats file
>> from the RIRs
>> (
>> and group together all those entries with a common value in column 8
>> (except for the entries corresponding to assignments and allocations
>> made by the RIPE NCC, where this information is, unfortunately, not
>> published by them in such a convenient format.)
> care to give a decode for the fields in that file?  :)

sure, I'll try.

for example:

Col 1 - RIR name, or 'iana'
Col 2 - The country where the entity 'resides' (or 'EU' in some cases), or 'ZZ' for reserved and unassigned blocks
Col 3 - 'asn' or 'ipv4' or 'ipv6'
Col 4 - The size of the allocation (asn or IPv4) or the prefix length (ipv6)
Col 5 - The starting value of the block
Col 6 - A date. For some registries this is the date of the original allocation - for others (ARIN) its not so clear precisely what this date signifies (!)
Col 7 - Status of the block
Col 8 - A hash field of the entity code (mu;ltiple allocations to the same entity have the same code) or null (RIPE NCC, IANA)
Col 9 - The source of the record (either "e-stats' where the original source is an extended stats file published by an RIR, or 'iana' if the data is lifted from an IANA registry)

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