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Consider the following scenario:
A Windows Server 2003 DNS server is configured to use conditional forwarders.
A DNS client sends a name resolution query to this DNS server.
This query requires forwarding to conditional forwarders.
In this scenario, the name resolution fails, and the conditional forwarders return an error message that resembles the following:
This issue does not occur if Windows Server 2003 DNS servers forward such a query to root hints.
This issue does not occur if you configured the default All other DNS domains option for the Forwarders setting.
This issue occurs because Windows Server 2003 DNS server earlier was not fully compliant with RFC 1035.
In some cases, the Windows Server 2003-based DNS server incorrectly sets the Authoritative Answer (AA) bit when it forwards the query to the conditional forwarders. Some DNS Servers check the AA bit when they receive queries. If the AA bit is set, the query is rejected. This occurs because the AA bit should be set only .in responses for which the responding server is authoritative for a particular domain.
To work around the issue, use root hints or the default All other DNS domains option instead of using the conditional forwarders.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about RFC 1035, visit the following Web site:
When this issue occurs, a network monitor capture may resemble the following:
1 Windows Server 2003 DNS server Third-party DNS server DNS:QueryId = 0x8022, QUERY (Standard query), Query for FQDN of type Host Addr on class InternetFlags: Query, Opcode - QUERY (Standard query), AA, RD, Rcode - Success ==> this is the query being sent to the conditional forwarder and notice that AA bit is set.2 Third-party DNS server Windows Server 2003 DNS server DNS:QueryId = 0x8022, QUERY (Standard query), Response - Not Implemented ===>error returned by the third party dns server