can I still map an IP address to its ASN number when the last octet is masked?

Question

I have a database of IP addresses whose last octet has been masked

IpAnonymizer.mask_ip("8.8.4.4")
# => "8.8.4.0"

Can I still use map these IPs to their respective Autonomous Numbers or the mapping is lost?

Thanks!

Answer 1

As far as I am aware there is no theoretical or technical minimum/maximum size of the prefixes that can be assigned to an ASN so I'm not sure.

(Practically of course larger networks and smaller prefixes are preferred to minimise the number of prefixes that need to be announced.)

Relevant may be that AFAIK the regional Internet registries (RIRs) only assign(ed) prefixes up to /24's which would always make only the first three octets relevant to map any IPv4 IP-address to it's ASN.

Note that in some cases even the only the first or the first two octets are sufficient to map the address IPv4 to a specific ASN.

For instance the 17/8 prefix belongs to AS714 i.e. Apple, that is any ip-address starting with 17 or 17.0.0.0 - 17.255.255.255