security - Will ASP.Net MVC's AntiForgeryToken Method work with Load Balancers?

Question

Using ASP.Net MVC v2.0, I am starting to research the use of the Html.AntiForgeryToken() method when submitting forms that process data. I can see it sets a hidden value in the form HTML and it sets the same value in a session cookie.

The question is will different web servers in a load balanced configuration create the same token in the HTML forms? It seems if they don't then the cookie and hidden form value wouldn't match and we would have a problem. Before I get into actually testing this in a LB configuration, wanted to check if anyone already has experience with this?

Thanks, Paul

Answer 1

If all machines across the farm share the same <machineKey>, everything will work. There are lots of resources on how to set this. There's also a tutorial on MSDN.

Note that the name <machineKey> is a bit misleading, since this is actually set per-application in ~/Web.config. So set the <machineKey> explicitly in your app's Web.config, then deploy across your farm.