We are operating a Windows 2008 Server R2 Standard with the DC, AD and DNS roles for our domain. The server is located at our primary site, with three remote sites connected through a VPN tunnel using our sonicwall routers.
For each location, our sonicwall routers are the DHCP servers and internet gateways. The sonicwall routers list our Domain Controller's IP address as the primary DNS, followed by two DNS servers provided by our ISP.
All routers and the Server have static IP addresses.
running "/ipconfig all" on client computers at all 4 locations returns the expected values. Default Gateway and DHCP returns the IP address of the sonicwall router at that location, and the DNS servers list the IP of our server, followed by our ISP's DNS servers.
And with that all set up, everything works fine - most of the time. However, we periodically have issues with clients being unable to resolve the names of other computers on our domain. This almost always happens on computers at our remote sites, not the primary site where the server is located at. When this happens, the computer is unable to ping any other computers by name, but it can ping them by IP address. Running "/ipconfig registerdns" will usually fix the problem, until it happens again at some random point in the future. None of the IP addresses of anything change in the process... not of the Server, the DHCP server, the internet gateway/router, the the client computer trying to resolve another workstation's name, nor the workstation who's name is being resolved.
Any clues what might be going wrong here and how I could fix it/work around it? Thanks!