I'm reading the document "Secure DNS Deployment Guide" got from the URL a poster gave in the list. The document said: When a user types the URL www.example.com into a Web browser, the browser program contacts a type of resolver called a stub resolver that then contacts a local name server (called a recursive name server or resolving name server). The resolving name server will check its cache to determine whether it has valid information (the information is determined to be valid on the basis of criteria described later in this document) to provide IP address for the accessed Internet resource (i.e.,www.marketing.example.com). If not, the resolving name server checks the cache to determine whether it has the information regarding the name server for the zone marketing.example.com (since this is the zone that is expected to contain the resource www.marketing.example.com). If the name server!ˉs IP address is in the cache, the resolver!ˉs ne query will be directed against that name server. If the IP address of the name server of marketing.example.com is not available in the cache, the resolver determines whether it has the name server information for a zone that is one level higher than marketing.example.com (i.e., example.com). If the name server information for example.com is not available, the next search will be for the name server of the .com zone in the cache.
I think the statement below is wrong?
If not, the resolving name server checks the cache to determine whether it > has the information regarding the name server for the zone marketing.example.com (since this is the zone that is expected to contain > the resource www.marketing.example.com).
How does the resolver know www.marketing.example.com is a domain name or a zone? www.marketing.example.com can also be a zone which has valid NS records. So I was thinking the resolver shall check the cache firstly to see whether it has the NS records for the zone www.marketing.example.com, if not, then to check the NS for marketing.example.com. Am I right?
Regards. _______________________________________________ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
