DNS Server May Not Recursively Resolve Some Names

• Microsoft Windows NT Server version 4.0

SYMPTOMS

Your Domain Name System (DNS) server does not recursively resolve names which contain a large number of IP addresses. However, the DNS server does resolve names which contain one or a small number of IP addresses.

CAUSE

When a DNS response contains more data than can fit in a UPD packet (more than 512 bytes,) it sends as much data that can fit into the UDP packet and sets the truncation bit, indicating that there is more data available.

The Microsoft DNS server discards packets with the truncation bit set and tries another authoritative server. The DNS server always receives the same response with the truncation bit set, so it eventually stops and returns SERVFAIL to the client.

RESOLUTION

The Microsoft DNS Server has been modified to accept truncated responses and return that response to the client.

Obtain the following fix, or wait for the next Windows NT service pack.

This hotfix has been posted to the following Internet location:

   ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/
   hotfixes-postSP3/dns-fix

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information. receive