I am running FreePBX 22.214.171.124 with around 40 extensions. All except 5 extensions are internal, the others are remote phones (all at the same IP address). Responsive firewall is running and has worked fine.
It has worked fine for about 3 months but for the past couple of days, the remote phones have dropped every few minutes. During this period the box has been totally inaccessible to the internet - except the IAX2 trunks to the provider stay active and the VPN connection already established (which we use to remotely support the system) works fine.