About this tool
An AS number identifies one network on the internet — one routing policy, one operator. This resolves the number to that operator three ways at once. Team Cymru give the AS name, country, registry and allocation date from the global routing table. RDAP gives the registry record itself: the organisation, the abuse contact, the allocation type and the event dates, plus the allocated block when the record covers a range rather than a single number.
RIPEstat supplies every prefix the AS currently announces, split into IPv4 and IPv6 with a total. Large transit networks announce thousands — AS13335 is over five thousand prefixes — so the list is capped on screen with the true total always shown, expandable in full, and copyable in one click.
Numbers reserved by the IETF are recognised before anything is sent. Private-use ranges (64512–65534 and 4200000000–4294967294), the documentation ranges, AS0 and AS_TRANS are never allocated to an operator and never appear in the public routing table, so the tool names the RFC that reserves them instead of returning three empty lookups.