How to setup remote offices?


We have been using 3CX for 3 years and I would like to give Wazo a try. Right now I am downloading a Debian image. What I want to know is, can I achieve a similar setup to our 3CX deployment in Wazo.

Currently, there is a dedicated server in a datacenter runs our 3CX main PBX and two SBCs in two different locations.

Is a similar setup possible in Wazo and how? I have seen documentation mentioning Class-4 SBC but it doesn’t how.

Yes, Wazo can handle that since, to Wazo, the remote phone, once connected, acts like a local phone.

Some things to be cautious about:

  • Security
  • NAT settings
  • e911
  • Router Port forward


  • Most IP phones have simple user/Password login and having them directly connected to the publkic internet is practically a guarantee to hacking. Have the remote phones behind a router/firewall.

NAT Settings
If your server is NATed and your remote phone is NATed, it is two NATs to transit and the settings are very particular about that. Have fun.

Satellite/Remote phones need to make sure they use a line registered to their location for e911. THat gets tricky with Wazo since the Outgoing context does not have a flag/filter for extension. See
for a more detailed discussion and coding solution for this.

Router Port Forward
If your remote phone is at a home address with dynamic IP address, you’ll need to use something like Travellin’Man (Ward Mundy) to keep that IP address in your setup for both Wazo and your Router for POort Forwearding if that is how you want to handle it. If a Fixed IP address is available, much easier.

Thanks Rambling.

I actually know Wazo can handle this, but I don’t know how. Documentation doesn’t mention how to use session border controllers (SBBC) to connect to a central PBX. Say for example we have 2 remoe offices and 1 central PBX on a cloud server. So we need SBCs installed in these remote offices and a Wazo main installed on the cloud. But… how?

usage of a SBC like in 3CX is not needed with wazo on remote offices

Alright, thank you. But I still don’t get an answer; How? I get that I don’t need and SBC. Then how I get to connect remote offices to one central PBX? By provisioning phones to connect to the main server? If so, then wouldn’t it be inefficient for 20 phones to try to connect to the remote server on the same network but individually? I can’t find a documentation for this usage schema.

I’m not sure about efficiency but 20 phones connecting to Wazo (remotely or locally) is not going to even come close to loading Wazo down and if you use compressed audio codecs instead of ULAW, the actual bandwidth will not be so bad.

One thing I did not mention in my first reply about security was because I did not realize you were connecting 20 phones in a remote location. Instead of port forwarding for RTP, use a VPN to connect the two sites and pass all Wazo traffic throught the VPN. Much more secure.

This is still not quite a solution in my opinion. Because you will have to use internet even for local extension dialing and this will ruin your internal communication. (I know because I have been there.) And I know Wazo already has an SBC feature set. The only thing I don’t know and can’t find is… How… There aren’t docs for it.

That I understand.

Can you not put a Wazo server in each office and link the servers so that only when a non-local extension is dialed do you need to go outside the office network?

I do not know how to do that with Wazo but I know that is possible with Asterisk and Wazo has a pretty powerful feature set so I expect it is possible with Wazo.

Maybe one of the really knowledgable folks can give advice.

My installation is pretty simple: home/home-office so I do not even used clusters; I use a system virtualized with proxmox and create a cold-standby in case the production system goes down, so not really sophisticated stuff here.