Subject: [LL17] ARPing vs. forwarding to router

From: Keith Moore <[email-masked]>
Date: Mon, 10 Feb 2003 11:46:47 -0500

I agree that the way that a LL-capable host sends to an LL destination
address is to ARP for that address (if it's not in the host's ARP
cache), and in general treat the destination as if it were
on-link, rather than to forward the packet to a router.

However the issue seems to be stated awkwardly.  

- It doesn't matter whether the packet to the LL destination is being
sent is a reply.  

- Also, "MUST NOT" forward to a router is fine, but "MUST ARP" has the
potential to be misread.  In general, a host is not required to reply
to an incoming packet.  If it doesn't want to reply, it shouldn't have
to ARP for that packet either.

It's probably better if the correct behavior is not stated in terms of
MUST.

Keith