I called and have an open call with phone power but I thought I'd post on this forum to see if anyone has any ideas.
I have a Linksys SPA2102 set up to work with phonepower. outbound calls are fine, inbound calls work for a few minutes after a power cycle and then it stops working.
I originally only have udp ports 5004-5012 and 5060-5061 opened up to the spa2102. To troubleshoot, I've now opened ALL ports to it on both udp and tcp. It seems to actually be working now.
So there have to be some other ports in play. Any one know what other ports are in use with the SPA2102? (When I get time, I'll probably do some tcp captures to see what's going on, but I was hoping someone has already figured it out).