>
> > I have in the past seen firewalls that dropped some critical packets but
> > allowed others through (in one case: RS/RA were fine but ND was
> > filtered, which led to IPv4 working in 3 second spurts, i.e. until NUD
> > kicked in).
>
> That's assuming there was no link-local communication, but just packets
> being send/received to the external network?
>
I wrote this up in 2009, so it's old and I'm told the Norton firewall bug
has since been fixed, but:
https://sites.google.com/site/ipv6center/icmpv6-is-non-optional
