A method and apparatus for use in a communications network in which a Mobile Node accesses the communications network via a proxy node. The proxy node is arranged to handle mobility signalling on behalf of the Mobile Node. At a mobility anchor function, such as a Local Mobility Anchor, a first Care-of-Address associated with the Mobile Node is registered. When the mobility anchor function receives a registration request to register a second Care-of-Address associated with the Mobile Node, it sends a request message to the proxy node acting on behalf of the Mobile Node. The request message instructs the proxy node to check whether the Mobile Node is reachable using the first Care-of-Address.