TheDNSMuseum
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Tools and toys

IP to ASN

Team Cymru maps an IP address to its autonomous system number through a structured DNS query, giving network operators a scriptable routing lookup.

ASNTeam Cymrunetwork operations

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Screenshot used in the talk for IP to ASN
Screenshot used in the original talk. Select the image to view it full size.

Team Cymru’s DNS service maps an IP address to autonomous-system information. The query name represents the address, and the response provides routing data.

For network operators, this is faster to script than a conventional WHOIS lookup. It is one of the strongest practical examples in the collection.

Primary source: https://team-cymru.com/community-services/ip-asn-mapping/#dns