What RFC and section defines what a resolver should do when it encounters a failure (so it tries to query ns1.site.com and it fails).
What RFC and section defines what a resolver should do when it encounters a failure (so it tries to query ns1.site.com and it fails).
RFC 1035 Section 7.2. This also references RFC 1034. Essentially the resolver needs to maintain the state of the request and timeout when there is no response so it can press forward. It appears the resolver should be performing multiple requests at the same time.
http://www.ietf.org/rfc/rfc1035.txt