wierd problem

I have a client who is having a problem with DNS. Most everyone can reach their web sites and send email, except those on attbi.com and rmi.net. For those people, dns lookups fail approximately 50% of the time. The domain used to be owned by someone who use rmi.net to host the domain. As far as I can tell, the gTLD servers return a correct response, and every other ISP appears to resolve the domain correctly. I have had no luck talking to ATT and RMI (earthlink) support (no surprise there). Any ideas how to diagnose this further. Thanks, Mitch -- Mitchell S. Baltuch Principal MountainStorm Technologies 806 W. 127th Court Westminster, CO 80234 303/324-8128 mbaltuch@mountainstorm.com http://www.mountainstorm.com