Methods and apparatus for authenticating a mobile node are disclosed. A server is configured to provide a plurality of security associations associated with a plurality of mobile nodes. A packet identifying a mobile node may then be sent to the server from a network device such as a Home Agent. A security association for the mobile node identified in the packet may then be obtained from the server. The security association may be sent to the network device to permit authentication of the mobile node. Alternatively, authentication of the mobile node may be performed at the server by applying the security association.