How to Resolve a "Cannot Communicate With Primary DNS Server" Error

TCP Scaling enables more data to be received through the network interface.

Microsoft's Windows operating systems have always had Internet capability, but Windows Vista and newer versions feature an addition. The option is called TCP Window Scaling and is enabled by default on Windows Vista and Windows 7 systems. Normally a system would be limited in the amount of network data it can receive by a "receiving window," but with TCP scaling, this limit can be expanded. But some network hardware is incompatible with it and will create the error "Cannot Communicate with Primary DNS Server."

Instructions

1. Turn on the computer giving you the error. Log in as an administrator.

2. Click Start and navigate to "All Programs." Expand the "Accessories" folder and right-click "Command Prompt." Select "Run as Administrator"

3. Type "netsh interface tcp set global autotuninglevel=disabled" into the "Command Prompt" window and press "Enter."

4. Restart the computer to finalize the settings.

References

• Tech Recipes: TCP Windows Scaling Errors - Cannot Communicate with Primary DNS Server
• LWN: TCP Window Scaling and Broken Routers
• Ohio IT Service Desk: Vista TCP Window Scaling