Comment 5 for bug 960126

So the filter seems not to like some thing about the addresses and ports. Which is unfortunately not the simplest part to read. So I tried to read a bit into the SIP RFC to find out more about the various fields sent.

Adding what we were discussing on irc: so another phone without the issues has the same data setup in the headers. The only difference we found was that working also sends from port 5060 (as indicated in via and contact) while the other phone comes from an unprivileged port but still has 5060 in the headers... maybe that is what the filter complains about.