The TechShow crew spend a couple hours last night changing and testing voip equipment. Allan and Pat finally have their VOIP phones working quite well, and Dann and I spent some time getting our respective Asterisk/Trixboxes to speak nicely to one another. We set up the servers with IAX trunking so my phones are an extension on his machine, and visa versa. Just for posterity and those of you looking to actually do this, I thought I'd share, since none of the documentation we found was entirely correct.
First off, all this was done through freepbx on trixbox. Add an IAX2 trunk: Unless I specify otherwise, leave all fields blank: Setting Server1 Server2 Dial Rules: 6|xxx 6|xxx Trunk Name: Server2 Server1 Peer Details: host=(Server2's hostname) host=(Server1's hostname) qualify=yes qualify=yes type=peer type=peer User Context: Server1User Server2User User Details: context=from-internal context=from-internal host=(Server2's hostname) host=(Server1's hostname) type=user type=user Next, add an Outbound Route: Setting Server1 Server2 Route Name: Server2 Server1 Dial Patterns: 6|xxx 6|xxx Trunk Sequence: IAX2/Server2 IAX2/Server1
And there you have it! Worked for us anyway :-)
The only other thing we both did, and I am not sure if this has any bearing whatsoever, is to edit the sip.conf file and add: externip = (your external host/domain here) localnet = 192.168.1.0/255.255.255.0 (or whatever your internal IP structure is)