Revisiting FreeBSD-SA-08:10.nd6 (or: avoiding IPv6 pain)

[Fernando Gont]

On 6/4/20 12:22, Philip Homburg wrote:
>> However, when a packet from an "off-link" network is employed, the
>> sending node has no way of knowing where to send the packet, unless it
>> simply swaps the src and dst mac addresses, and uses the source address
>> of the packet as the destination addresses.
> 
> No, a node can just use the normal IPv6 send mechnisms to send a NA
> message. If the destination is off-link then the packet gets sent to the
> default router.

Agreed. I missed this. Although there might be corner cases where this 
doesn't apply -- i.e., for some reason you have no routes.

But yes: use normal IPv6 send mechanisms. And also probably motivate 
that nodes use the address of the sending interface (strong-end system 
model, per RFC1122).

Thanks,
-- 
Fernando Gont
e-mail: fernando at gont.com.ar || fgont at si6networks.com
PGP Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076 FFF1