Well, the IT guy finally found the problem in the sonicwall. I don't have specifics, but he said it was due to a nat rule in the sonicwall that caused the phones to register to the wan ip instead of the private ip of the TDE100. After disabling that rule phones started working.

Thanks guys for the help and by the way the voip test tool came in very handy for troubleshooting this problem. It proved to the IT guy that something was still going on in the sonicwall.

Last edited by MichaelV; 01/31/13 12:49 AM.