Connecting two Freepbx together through a VPN

At some point I would like to connect two freebpx systems together. The problem is I have no clue how but I do know it can be done. I read and saw a video of a guy connecting two freepbx systems together but not sure how it was a very old video. I think the video is more then 5 years old. But I can not remember.

I have two freepbx systems setup. There are two networks different external ip. Both internal IP addresses are and the second IP address is The one thing the networks have in common is that they are are connected together through a VPN server. both networks can see each other as well as talk to each other.

It’s just the thing is how can I connect them together so I can transfer a call that is on an extention from one freepbx system to another? Does anyone know of a site that I can look at or any information How I can start this crazy idea?


Hey Joseph,

Not a crazy request at all and part of the basic functionality of FreePBX.

First verify that the two PBXs can actually talk to each other over the VPN. Your simplest way to do that would be to just try and ping each unit from the CLI of each device.

If that’s working correctly then all you really need to do is setup a pjsip trunk with the IP and port info for each unit and then bind each to an outbound route that references the extensions for each destination phone system.

The only caveat here is that you can’t have overlapping extension numbers, they need to be different between units so that the systems knows how to route the calls.

The only other thing you’ll want to do is specify the Local IP subnets for each network on both units under Settings → Asterisk SIP settings.

You will get better access to the other boxes endpoint if you use ‘from-internal’ as the context for the tie trunk.

That too. Thanks @dicko.

the Ext numbers on frist pbx is 700 to 710 and second pbx ext start at 800 to 810.

The two pbx can see each other I can even ping bwteen them also ssh between them with no problem.

Hey dicko, How can I do that?

If you do some googling and searching here and otherwise online you should be able to find the answers you need. Here is one such thread from a couple of years ago:

Create a trunk on both machines that connects to the other machine, you can use chan_pjsip or chan_sip I will offer that an iax2 trunk with ‘trunk=yes’ is the most efficient way. (hehe, just waiting for the barrage of ‘what? are you stupid!’ from the folks who have never actually tried it . . .) use the from-internal context and ivr’s and ring groups will be available if you are carefull with your numbering

I setup the old pbx over 5 to 7 years ago and never setup another freepbx after that. I honestly don’t remember what I did. I set it and forgot it. I been recently trying to help friends with there problems withere there freepbx stuff. Because they found out I setup a freepbx so long ago and told them I don’t remember. But still a friend I’m I try to help best I can.

Thank you. This helps a lot.

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