On Mon, 28 Nov 2005, Glen Kent wrote: > to different Autonomous systems. > Is there a central/distributed database somewhere that can tell me > that this particular IP prefix (say x.y.z.w) has been given to foo AS > number? We have archives of much of that information (historical whois), and we've been working on databasing it, but that's unfunded work, so it's going slowly. Basically, we get bulk data from the five RIRs, and try to parse it into a structured database. For the ones like ARIN and LACNIC, that are coming out of a similar relational database, it's not too difficult work. For others, it's largely manual. > I tried searching through all the WHOIS records for a domain name. I > get the IP address but i dont get the AS number. > Any clues on how i can get the AS number? If you just want this for one thing, not lots, you can just track it down by hand. Check to see if the address space is being announced, and if so, by what AS. Then check the RIR whois for that AS, and see who it is. If it's not being announced, start looking through whois for substring matches against likely bits of the name of the owner of the address space. -Bill