Network name is no longer available Win 2008 host Win XP guest on VMWare Server

A law firm in Long Beach CA who is using VMware Server to host 3 virtual Windows XP machines called me to troubleshoot an odd networking problem.  They were experiencing network problems when transferring larger files over the network.  The problem would occur when trying to copy or save a larger file from the guest Windows XP machine, to the host server running Windows Server 2008. 

First steps of troubleshooting was to install updated network drivers for their Dell PowerEdge T310  Server.  Got the drivers from Braodcom, but after the reboot the problem persisted.  The next step was to disable all the unnecessary features of the network driver: Flow Control, CheckSum Offload, Large Send offload, Receive Buffers, Receive Side Scaling, Transmit Buffer, and so on.  Once again, after the reboot the networking problem remained.  Now that the ideas off top of my head have run out, I turned to the internet.  Found an article that suggested adding “AllowBindingToMACBridge" but that didn't solve the problem. Next I followed another suggesting of disabling DOS on the host machine, by adding a DWORD DisableDOS to “HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanManServer\Parameters” after the reboot, there were no changes, so kept on troubleshooting the problem.

Finally I came across a suggestion of disabling or setting DisableTaskOffload to 1.  Windows server 2008 has a default value of 255 which means not configured.  I opened regedit, navigated to: “HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters” found DisableTaskOffload modified it, and changed it from 255 to 1.  Restarted the server, turned on the virtual machine guests, and sure enough, problem solved!

On August 24, 2011, posted in: Vmware by