Dynamic IP issue with sip provider - trouble hearing inbound

I am setting up a new Asterisk box and we are having trouble hearing inbound callers. Outbound is working fine.

We have been trying to resolve the issue with our SIP provider (BroadVox, USA) and they are telling us that the problem is related to our IP address. They have our account setup to use a dynamic WAN IP address but they say that our PBX is sending them our LAN IP address which is what we cannot hear the inbound callers. I have looked through the Trunk configuration options, and the Inbound Route options, but I cannot see a setting that lets me control what IP information is being sent to them.

We have another Asterisk box up and running at a separate location with BroadVox and it works fine. However, at the other location the Asterisk box is connected directly to the WAN with a static IP.

Can someone please tell me how we might resolve this problem. I am trying to understand how to configure an Asterisk box behind a router with a static “LAN” IP address and still be compatible with our SIP provider’s authentication method.

You need to set externhost (with dynamic DNS), or use the stun options, in sip.conf.

However, ISP’s often use dynamic addresses to frustrate the use of servers, so, you will still have problems if they play the trick of changing your IP address at intervals.

As Asterisk doesn’t have a fully formed trunk concept, and there is certainly no Trunk configuration options, you will need to consult the supplier of your Asterisk GUI to find out how to configure the GUI to achieve this. Maybe someone here uses that GUI, but you haven’t said which it is (nor, for that matter, which version of Asterisk).

There are lots of other potential issues with NAT configurations, but you haven’t provided enough information to allow people to work out whether they apply in you case.

Thanks. I resolved the problem by changing the NAT settings in FreePBX/Asterisk SIP Settings. I changed NAT to Dynamic, entered the router’s IP address and subnet mask, and it seems to be working now.