How to switch off SIP ALG on Digital Voice for Business
What is SIP ALG?
Session Initiation Protocol Application Layer Gateway (SIP ALG) is an application within many routers. It inspects any Voice over Internet Protocol (VoIP) traffic to prevent problems caused by firewalls, and if necessary modifies the VoIP packets. Routers will often have SIP ALG activated by default.
What problems can SIP ALG cause?
SIP ALG can stop your Digital Voice for Business devices from:
- Registering on the service.
- Making internal calls.
- Receiving incoming calls.
It can also cause voice quality issues.
If you have BT Business broadband through the BT Business Hub 5 or any of the BT Business Smart Hubs, this won't be a problem as the SIP ALG will be disabled. However, if your BT Business Hub is reset for any reason, SIP ALG will automatically be activated. If you need to switch it off, follow the steps below.
If you're not using BT Business broadband, or BT Business Hubs or routers, you'll need to disable SIP ALG on the router you are using.
When you order Digital Voice using non-BT broadband, we'll run a test and be able to tell you if SIP ALG is switched on. If this is the case, you'll need to disable it in order to use your Digital Voice service.
How do I switch off SIP ALG on my BT Business Hub?
Firstly, make sure you're using a computer that's connected to your network. Then follow these simple steps:
- Open a browser (such as Internet Explorer, Firefox, Chrome or Edge) and type 192.168.1.254 or businesshub.home in the address bar.
- On the BT Business Hub home page which appears, tap Advanced Settings.
- Enter your admin password, unless this has been changed. Your default admin password can be found on the bottom of the BT Business Hub, or on the plastic pull out.
- Tap Continue to Advanced Settings.
- Tap Firewall, then Configuration, and scroll down to Application Layer Gateway.
- Select Yes next to Disable SIP ALG, and tap Apply.
You've now turned off SIP ALG on your BT Business Hub.