Remote Sip Extensions

So I have installed and finally got working FreePBX with AsteriskNOW. I have installed Media5 fone on my iphone and am trying to get that to work as a remote extension.

If I dial the iphones extension from office phone the call connects and I can hear both sides of the conversation.

Also works in reverse (iphone calls office extension)

If I use it to call outside the the Asterisk server it will connect, ring the extension, but then neither party can hear the other.

I’ve tried following the instructions at:
http://www.freepbx.org/support/documentation/howtos/howto-resolving-audio-problems
which didn’t help so I’m at a loss on what to do now.

OK, so if I have the phone on our internal wireless network and have it pointed directly at our server eg. 192.168.1.1 instead of xxxxx.dyndns.com it works perfectly.

Also, when the server is xxxxx.dyndns.com and I call say a hotel, I can hear their menu system, but when I ask to be transfered to an operator, it drops the call. PBX status show the call to be nonactive but the phone itself looks like its connected.

Thoughts

Two days of chasing down one little checkbox!

On netgear router ensure that under NAT filter Disable SIP ALG is checked