The present invention relates to a method and apparatus for allocating a value of a parameter to a client host by an access point in a communications system comprising an IP network, where the parameter value has previously been assigned to the same client host by a first parameter-value assigning node. The method includes using a DHCP message to carry a signed information package from the first parameter- value-assigning node to the access point via the client host. The signed information package comprises information on a preferred value of the parameter and a signature of the first parameter- value-assigning node. The signature can be verified by the access node, and if true, and if the preferred value is available for allocation, the access node will allocate the preferred value of the parameter to the client host.