Hi,
The IP number is given to your B2 by your house router. The B2 has to accept the number it is given, it can play no part in the process.
There is a way to give the B2 the same IP number all the time, but to do this you have to log on to your Routers Admin page and using the tools provided, assign your B2 a fixed IP address.
Nearly All manufacturers Routers provide tools for doing this but they all achieve this in a different way. If you tell us the make/modle of your Router we may be able to help you do this.
Fred