[savi] A query and a kind of potential attack in draft-bagnulo-savi-fcfs-01

[ZhangDong <zhangdong_rh at huaweisymantec.com>]

Hi Marcelo,

You mentioned special cases in section2.4 in fcfs-01. One of the special cases is o  Anycast i.e. multiple hosts using the same source address to send packets.
I am puzzled.  As described in RFC2460:
   o  An anycast address must not be used as the source address of an
      IPv6 packet.

   o  An anycast address must not be assigned to an IPv6 host, that is,
      it may be assigned to an IPv6 router only.
How does the case that multiple hosts using the same source address to send packets happen?
In fcfs-01, the word "anycast" means the case that multiple link-layer addresses (such as MAC)use one IP address?


The section 3.3.1 ARP-based Neighbor Unreachability Detection procedure in fcfs-01 designs a mechanism of NUD based on arp. The savi device sends an ARP REQUEST packet as the NUD message. Suppose that an attacker has initiated arp cheating. The attacker responds the arp request whic is the NUD message. In this case, when the user really changes another IP address with the same MAC, because of  the NUD response of the attacker, the binding o
f IP and MAC in savi device wiil not be update. And then, the packets sent by the new IP address of the user will be discard by savi device.

Will this problem happen?  Do i have misunderstanding?

Thank you very much.



Dong Zhang