My company is working together with Nokia to test N80 IE for SIP application. We received the latest development firmware for tests. This firmware handles STUN protocoll during registration. We made many tests with different type Linksys and other wifi routers. The result is that with most of the Linksys boxes the N80 does not work, it even cannot register with SIP server. We made IP dumps in the phone and in the server also and it seems that the implementation of the STUN protocol is not correct in the N80. It works on full cone nat, but does not work on any restriced nat. We told the problems to the local Nokia guys, but they had very strange reaction. They said that the development was finished and this firmware would be the commercial one. If that is the case, Nokia will have huge problems if they introduce N80 IE with this firmware on the market. It will work only on very limited number of wifi routers. Can somebody help me from Nokia to discuss and fix this problem? I can provide all SIP logs both for successfull and faulty registrations.