I am having an issue with a Windows Server 2008 SP1 DNS server that I cannot seem to resolve. I have found relevant documentation on the Internet and Experts Exchange but cannot seem to relate it to my situation. I have a root hints DNS server that struggles with caching a single domain, "wildblue.net". It appears that the NS record for the domain as provided by their name server is persisting in the DNS cache longer than than the A record associated with that domain name. Once the A record has expired, the NS record is unable to be resolved and a lookup on that domain returns "Server Failed". If I clear the cache, the NS record is deleted and subsequent requests pull a whole new zone file with name server A record which returns correct responses. I have tried setting the MaxCacheTTL to 2 days as recommended by a number of websites but this has not resolved the issue. When I clear the cache both the NS record and the A record have 24hr TTL's but at some point the NS record must be getting refreshed. When looking at the cache this morning after clearing it yesterday evening, the A record was down to 6hr TTL and the NS record had a 23hr TTL. Left unchanged this A record would expire and subsequent DNS requests would fail.
What is causing these NS and A records to become mismatched and allowing the A record to expire before the NS record? The wildblue.net name server is returning a TTL of 15min for the NS record and 24hrs for the A record. Is my DNS overwriting the TTL of the NS record? Is this a problem on wildblue.net's end or a problem with our DNS server?
Thanks for your help!