Gaurav Puri writes: It is a requirement of mobile IP that the source
address of ISAKMP packets is Careof address when IKE is initiated by
MN at foreign network. Consider IKE Phase 1 Authenticated With
Signatures:-

        Initiator                          Responder
       -----------                        -----------
        HDR, SA                     -->
                                    <--    HDR, SA
        HDR, KE, Ni                 -->
                                    <--    HDR, KE, Nr
        HDR*, IDii, [ CERT, ] SIG_I -->
                                    <--    HDR*, IDir, [ CERT, ] SIG_R

if we implement this using Main mode, we have to maintain/store the
information about the messages exchanged(like nonce values and keying
information etc) b/w MN and HA till the ID of MN is revealed(i.e the
5th message).

this information has to be maintained regardless of the authenticity of the
initiator. the sender can be authenticated only after the 5th message.
Isn't it a severe security threat?? HA can be flooded with fake
messages....

please clarify

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Francis Dupont responds: This is an issue for IPsec which is not bound
to Mobile IP, i.e., this mailing list is not the right one.

BTW this problem was discussed in the IPsec WG and proper
implementations can't be so easily DoS-ed. Look at sections 2.6 or
2.12 of draft-ietf-ipsec-ikev2-05.txt for instance.

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