These are the steps to make Siri and Apple iCloud functional on the IWU network.
Siri was not working on the IWU network.
These are the steps to resolve the problem.
After investigation it has been found that iPrism was the culprit in causing Siri not to work on the IWU network. By allowing any incoming IP to the iPrism system to have unfiltered access to Apple's 22.214.171.124/8 subnet Siri began to function correctly. This was also the same process that was used in allowing the Apple iCloud feature to function as well. Two additional IP ranges maintained by Apple have been given unfiltered access from any internal IWU IP address to enable access to their iCloud features.
Bill Emmett 22-Mar-2012