This problem may occur if the DNS server is queried for a non-"A" record, and the server replies with an authoritative response that returns NXDOMAIN or NAME_ERROR (Response Code, or RCODE, 3) even though an "A" (or Internet Protocol version 4, or IPv4, host) record for the queried name exists on that DNS server. NXDOMAIN or NAME_ERROR in the response indicates that there are "no records of any type for that name." Microsoft has found that some DNS server software does not support "AAAA" (Internet Protocol version 6 or IPv6) records and incorrectly responds with NXDOMAIN even though an "A" record exists for the site.
For example, this problem may occur when a Windows client computer that is running IPv6 tries to access a Web site. The Windows client will try to resolve the host name (for example, www.example.com) on behalf of applications that support both IPv6 and IPv4. To do this, the Windows client will query for both "AAAA" records and "A" records, unless the application specifies which protocol to use. If the DNS server replies with an authoritative response that returns NXDOMAIN or NAME_ERROR, Windows will return this response to applications, such as Internet Explorer. Because of this, the application will fail to resolve the host name and will be unable to access the site. Note that Windows clients will also cache this negative response. This prevents additional queries for this name from succeeding until the client cache is cleared.
Important In this example, if the DNS server that is used by the Windows IPv6 client caches negative responses, name resolution will also fail for other client computers when they use this same caching DNS server. This issue occurs regardless of the subsequent query type and regardless of whether the other client computers are running IPv6 or IPv4 only.