Subject: A problem with proxy address and ND probes?

From: Markku Savela <[email-masked]>
Date: Fri, 14 Mar 2003 17:39:15 +0200

I just did some experiments with configuring a IPv6 global proxy
address for an interface, and observed (for me) surprising effect:

Everything went fine until the other end decided to do ND probe for
the proxy address:

   dst=proxy src=x [... ICMP NS ...]

Normal packet handling just looks at the IP header and decided quite
correctly that this packet is not for me, but needs to be forwarded to
the proxied host. => probes fail

Seems that to get proxy address handling to work, one must in addition
to looking at the destination address, also peek inside packet and
look if it contains neighbor discovery packet for proxied address, and
if so, instead of forwarding, treat the packet as if addressed to
self.

Of course, this is doable, but it kind of adds an "ugly wart" into
normal packet processing path. Presumably, MIP6 Home Agent
implementations already handle this somehow.

Just thought to report this. At least for me, this aspect of the
proxying didn't occur to me while implementing ND...

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