DNS on Windows Server 2003, 3rd Edition

Iteration

Iterative resolution doesn’t require nearly as much work on the part of the queried name server. In iterative resolution, a name server simply gives the best answer it already knows back to the querier. No additional querying is required. The queried name server consults its local data (including its cache, which we’ll talk about shortly), looking for the data requested. If it doesn’t find the answer there, it finds the names and addresses of the name servers closest to the domain name in the query in its local data and returns that as a referral to help the querier continue the resolution process. Note that the referral includes all of the name servers listed in the local data; it’s up to the querier to choose which one to query next.