Disable SIP ALG on BT Business Hub 5 (and others are similar)

* In your web browser, go to 192.168.1.254 (this is the default IP for BT's routers - if you have changed yours enter yours here)

* Click on Advanced Settings

* Enter the admin password.

* The default password can be under the BT Business Hub or on the plastic card you can pull out from behind the Hub.

* Click on 'Continue' to Advanced Settings

* Click on 'Firewall' then 'Configuration' and scroll down to 'Application Layer Gateway'

* Beside 'Disable SIP ALG' select 'Yes' and click Apply