ASP.NET 2.0 Machine Key

When moving a fiddler based web test to a remote machine a Viewstate Mac error was received.

This was caused because the viewstate is encoded using a MachineKey which is unique to the machine that the request was formulated on. So when the viewstate is read by the remote machine this throws an error.

This can be overcome by adding a hardcoded machineKey to the web.config file as detailed in the following article.

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnpag2/html/PAGHT000007.asp