Though Mobile IP cannot reduce or eliminate this vulnerability, Mobile IP can authenticate the Mobile IP messages. The default algorithm used is MD5, with a key size of 128 bits. The default operational mode requires that this 128-bit key precede and succeed the data to be hashed. The foreign agent also supports authentication using MD5 and key sizes of 128 bits or greater, with manual key distribution. Mobile IP can support more authentication algorithms, algorithm modes, key distribution methods, and key sizes.
Tunneling can be a significant vulnerability, especially if registration is not authenticated. Also, the Address Resolution Protocol (ARP) is not authenticated, and can potentially be used to steal another host's traffic.