SBS 2008 VPN Connection causes blue screen
Posted on 2010-11-25
We recently installed a new HP SBS 2008 server as a single domain controller. During installation DHCP address range was picked automatically from the router (10.0.0.1 - 10.0.0.255) and the server itself was assigned 10.0.0.2.
All was working well except when I connected my iPhone using VPN. After two or three connections and disconnections the server consistently failed with a blue screen. The memory dump indicated issues with the network driver. Other devices and PCs did not cause this issue.
After extensive investigation by HP, where no hardware fault could be found, the cause was found by ourselves to be the allocation of IP addresses to the WAN Miniports used by VPN. In this case DHCP was allocating the server IP itself (10.0.0.2) to the VPN connection and it was this conflict that caused the blue screen
Our solution was to change the IP address of the server to one much higher up the range (.222). The WAN Miniports always seem to be allocated low available numbers such as .188.8.131.52 etc.
Thought this information might be useful to others and would appreciate any comments from those of you who understand these things as to why it happened.