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How to switch off SIP ALG on Cloud Voice
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How to switch off SIP ALG on Cloud Voice

What is SIP ALG?

SIP (Session Initiation Protocol) ALG (Application Layer Gateway) is an application within many routers. It inspects any 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?

This can stop your BT Cloud Voice devices from:

  • registering on the service
  • making internal calls
  • receiving incoming calls
  • and, can cause voice quality issues

If you have BT Business access using the BT Business Hub 5 or above, including Smart Hub, this won't be a problem as the SIP ALG will be disabled. However, if your Business 5 Hub is reset for any reason, SIP ALG will automatically be activated. See the steps below on how to turn it off.

If you're not using BT Business access and/or BT Business Hubs or routers you'll need to disable SIP ALG on the router you are using. When you order Cloud Voice over non BT access, 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, to be able to use your Cloud Voice service.

How do I turn off SIP ALG on the Business Hub 5?

First make sure you're using a computer that's connected to your network. Then follow these simple steps:

  1. Open a browser (Internet Explorer, Firefox etc) and type or businesshub.home in the address bar.
  2. On the BT Business Hub home page which appears, click on ‘Advanced Settings’
  3. Enter your admin password (unless this has been changed, the default admin password can be found on the bottom of the Business Hub 5 or on the plastic pull out on its back).
  4. Click ‘Continue to Advanced Settings’
  5. Click ‘Firewall’ then ‘Configuration’ and scroll down to ‘Application Layer Gateway’
  6. Click Yes next to ‘Disable SIP ALG’ and click ‘Apply’

You've now turned off SIP ALG on your Business Hub 5.

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