An arrangement and a method is provided for discovering candidate access routers in a mobile IP (Internet Protocol) network to enable seamless IP handover of a mobile node between access routers. A server element (19), which is separate from the access routers (11, 12) and the mobile node (MN), is provided with access router information relating to one or more access routers and with information identifying the access router serving the mobile node and reachability information about one or more access routers other than the serving access router that are within reach to the mobile node. The address of at least one of said one or more access routers within reach to the mobile node is determined in the server element on the basis of the provided information.