Can't connect to alternate DNS server

I've been asking this quetion all over the place and no one seems to have a
clue about it. This is definitely a strange one. I'm running DNS on AD
Windows 2003 SP1. I recently noticed that Windows XP and Windows 2003 clients
do no automatically fail over to their alternate DNS server if their primary
DNS server is disconnected. In others, if the server listed as the primary
DNS server in the tcp/ip properties is disconnected from the network, Windows
XP and Windows 2003 clients do not automatically connect to the server listed
as their alternate DNS server under tcp/ip settings. However, Windows 2000
clients do not have this problem. The failover to the alternate DNS server
propertly.

It does not matter which server is set to primary or alternate. If I reverse
the servers I still get the same problem. When running wireshark to sniff the
traffic it appears the clients do not even make an attempt to contact the
alternate server. They simply fail on the primary and then give up. Has
anyone seen anything like this? I can't find any answers anywhere on this
issue.