We're having a strange problem with DNS. On the user side, it appears as a temporary inability to get anywhere on the web. Even to an internal website. IE/Firefox just hang up; a page refresh doesn't work; reloading the app often does, as does waiting 5-10 minutes and trying again.
On the server side, I'm seeing event 4521 every 3 minutes, with the detail:
"The DNS server encountered error 9002 attempting to load zone . from Active Directory. The DNS server will attempt to load this zone again on the next timeout cycle. This can be caused by high Active Directory load and may be a transient condition."
This is a Windows 2003 Small Business Server, SP2. Running our own DNS server internally, with the server pointed at itself (via it's own IP address, as recommended for 2003) and no secondary DNS server listed. The DNS server is configured with forwarders (we use OpenDNS to limit non-work activities).
I've already been to eventid.net and tried the various suggestions there. I'm unable to create a '.' zone, an attempt to do that creates an error about zone creation. There is no '.' zone already in evidence. I've tried the sequence in KB articles M298148, M323380 regarding removing the '.' zone, with no results. I've even gone through the suggestion in KB M294328 on how to reinstall a dynamic DNS Active Directory Zone to rebuild our DNS server entirely, with no change.
I know there was another server in this domain at some point; it had Exchange on it and when I took over I had to (carefully) remove evidence of it from the Active Directory, because the prior sysadmin just ripped it physically out without a graceful demotion and removal. I'm guessing something similar happened to the dns, since the problem was recreated as soon as I got the DNS service rebuilt.
Oh, and just for kicks, I tried configuring the DNS server without forwarders, just to check; no luck, same errors and sporadic failures on the user side. I have one user who is pointed at another, external, DNS server; he has none of the sporadic failures.
Any suggestions gratefully received; I'm really tearing my hair out on this one.