Unifi Talk : Gamma SIP Trunks

Unifi recently (and finally) brought Unifi Talk to UK shores, having an ISDN2 PBX that is almost 2 decades old it seemed like the perfect opportunity to upgrade.

One small snag, Unifi isn’t currently supporting number porting to their Talk service for the UK.

Our current provided offers a SIP Trunk service supported by Gamma – so Unifi Talk is just SIP how hard can it be…

Talk is essentially Freeswitch behind a UI and Unifi goodness, so its a reasonably well documented and understood system, and can support practically any SIP provider you’d care to imagine.

Talk configures two scopes internal and external.

Internal listens on port 5060, and External can listen on a registered port or when Static Signaling is enabled port 6767

Gamma has a couple of interesting requirements:

  • Uses Static IP as “Auth”
  • Uses Fixed Port 5060 signaling.

This presents the first problem, we can’t simply port forward 5060 from the internet to 5060 internally as Talk will treat that SIP traffic as internal and the ACL will block it.

We instead need to move the traffic with a firewall rule, taking external traffic on 5060 and forward it to 6767 (the static signaling port) with that completed we also need to allow Internet In traffic for that local forward.


Step 1) Setup Port Forwarding Rules from Gamma Provided IP ranges

    Step 2) Configure FW Rules

    Step 3) Enable Static Signalling

    Gamma doesn’t support registration, or allow inbound ports to be easily change we therefore need a fixed port to forward. Handily Static Signaling exists.

    Step 4) Configure Unifi Talk SIP Provider

    Step 5) Test

    That should be all that is required, if you have one way audio confirm port forwarding and Internet Local rules are properly configured.