[Asterisk-Users] internal & external SIP

[Jon Lawrence]

In response to myself.
Setting specific codecs has indeed fixed the problem.
Q - how and why ?
when the remote phone has a vpn directly to my internal LAN, everything works 
perfectly when codecs=all. But when it's connecting in from a public IP 
everything goes pear shaped.
Can anyone give a even a clue as to why this happens ?
Or is it like many other things that don't make sense - it just does :)

Thanks to everyone that offered advise.

Jon