MAC Validation failed on web cluster

[imnotso]

I have an C# .NET web app...small but perfectly formed. We have upgraded to .NET2. We now get an error on navigating off 1 page. When the user clicks 1 of the 2 buttons the app crashes with the well know error..... 'Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster. Now before you all shout 'put the machine code in the webconfig', I have, on all 7 of the the front ends. And it hasn't cured it. And if it is so important, then how come the rest of the app was working fine without it? Now I know it's related to viewstate and the fact that the postback can go to another server but I don't know much more. I have added <enableViewStateMac="false">, this works a treat, cures my problem but has been deemed an unnacceptable fix by our solution architect. Something to do with security. And suggestions on my next move would be welcome. Thanks

[Parwej Ahamad]

Hi, I am also trying to reproduce locally this issue. So that I can trace more specific solution. For the mean while please go throught with this thread: http://forums.asp.net/p/955145/1173230.aspx[^] http://blogs.msdn.com/tom/archive/2008/03/14/validation-of-viewstate-mac-failed-error.aspx[^]

Parwej Ahamad http://parwej.wordpress.com/