Subject: Peer address update and DPD

From: Ravi <[email-masked]>
Date: Mon, 14 Apr 2003 10:08:00 +0530

Hi All,
        I saw in one of the recent emails that, DPD is should be used to check the existence of
        new updated address by the receiver, before start using this. May somebody give the
        reasoning for checking the liveness of the address. Since, the notification message
        comes with new IP address as source IP of the notification message, does this itself
        indicate that that IP is reachable. 
      
Regards,
Ravi.

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Ravi Kumar CH
Rendezvous On Chip (i) Pvt Ltd
Hyderabad, India
Ph: +91-40-2335 1214 / 1175 / 1184

ROC home page <http://www.roc.co.in>

---

From: Francis Dupont <[email-masked]>
Date: Mon, 14 Apr 2003 18:57:17 +0200

In your previous mail you wrote:

           I saw in one of the recent emails that, DPD is should be
  used to check the existence of new updated address by the receiver,
  before start using this. May somebody give the reasoning for checking
  the liveness of the address.

=> easy: this is a return routability check: a request is sent to
the peer at its new address and when the response comes back one knows
the peer is able to receive messages sent to this address. This is not
high security but you catch attackers using random fake addresses (note:
attackers knowing the keys negociated in phase one, i.e., this is more
an issue about the trust one puts on its peer than other thing.

Regards

[email-masked]