Hi All, Thanks for all your responses.
Understood about the potential N:1 relationship between as-set and aut-num, that makes sense. Thanks for the pointers to IRR Explorer too. I am interested in automating this stuff as someone mentioned so just as a start I might be able to query one of [RIPE, PeeringDB, IRR Exploring], if I get <> 1 AS-SET back, try the next one, then the next etc., then contact someone manually if all three have method "fail". Cheers, James.
