I am trying to configure my router and asterisk to allow incoming and outgoing calls but without allowing extensions to register off-site. Basically I need to be able to dial a 7-digit Sipgate number that will then ring on the phone configured for that account (at another site)
The only way I have managed to achieve this so far is by setting up a 2nd account (not on Asterisk) on the IP phones I wish to dial from. Asterisk seems to accept incoming calls but not make any - I get the 'all circuits busy' message. I did manage to get this working by allowing port 5060 through NAT and port forwarding, however this also meant that extensions within Asterisk could be registered from anywhere on the internet - something I do not want to be possible.
As it seems like an outbound block, I do not understand why it can't be overcome and the only way I can think of configuring the phones to be able to call each other is to set up a VPN between both sites, which is something I would like to avoid.