Connection-specific DNS suffix strange!

On our total Windows 2000 network, all my clients have a weird issue. If you do a “ipconfig”, all show the “connection-specific DNS suffix” to have a “51” added to the end of the “domain.com” name. instead of “domain.com”, it shows “domain.com51”.

Any ideas what is causing this? I have restarted my DNS service on the AD and doublechecked the network configurations on the client stations.