Find out what phone network your friends and family are using
WhatNet will also tell you what geographical location a landline number is in. for example: 0115976XXXX would show as Nottingham.
WhatNet can only tell you the original network of a number. If the number has been ported to another network, or is part of a network run off another network (e.g. GiffGaff) then WhatNet will show the original/parent network.