After you have received confirmation that your IP address option has been changed, do the following:
Disconnect from your broadband service. The next time you connect, your computer and router/hub will pick up the settings for your new service automatically.
Whether you have a Single Static IP or a range of Static IP addresses, your router should be set to Obtain an IP address automatically. All Static IP addresses are applied by BT based on your Username and Password, therefore as long as your connection details are correct you will always be assigned your Static IP addresses.
For system administrators
If you have a range of No NAT IP addresses please note that the router will pick up a dynamic peer address and the routing for the No NAT range will be bundled to that dynamic peer address. This means that the routers WAN IP address will be dynamic and will possibly change when the router is re-booted. Once configured in the BT Business Hub the No NAT IP addresses can be assigned to individual devices and they will then be Static Public No NAT IP addresses, each being a fixed IP with its own port stack.
If you are using a 3rd party router there are several ways you can implement our No NAT range. If the router has WAN IP aliasing then just specify the alias and setup port redirects as required. If the router can disable NAT then the static range can sometimes be assigned as the LAN IP range. You can also use our No NAT range by adding static routes with one to define the gateway address (this would be the router address of the range) and another to point each usable IP to the router/gateway address.