On 2017/06/22 16:05, Marc Peters wrote:
> Am 06/22/17 um 15:30 schrieb Stuart Henderson:
> > 
> > How are your PF rules? Do they allow NDP packets to pass? If you're
> > unsure, I would try "pass log inet6 proto icmp6" or similar.
> > 
> > (this might be a bit of a surprise if used to IPv4 where address
> > resolution is done by a separate protocol that PF doesn't block).
> > 
> 
> I don't block any icmp6:
> pass inet6 proto icmp6 all
> 
> is already present in my /etc/pf.conf

Are there any other rules which might interfere with this one? This
issue feels very much like NDP not getting through in some circumstances.

For instance I had problems at an IXP where one peer was sourcing the
NDP from an fe80:: address which was getting blocked by a too-restrictive
"drop junk packets" type of rule. Everyone else was sending them with a
"real" source address which wasn't triggering that rule - it took a
while to track down!

I would want to be 100% sure of this before digging deeper (e.g. with
"match log(matches) proto icmp6" at the top of the ruleset and watching
pflog when flushing ndp).

I think the step after that would be seeing what you get from nd6 debug
messages, either you can build a kernel with the ND6_DEBUG option, or if
you can break into DDB, you don't actually need a new kernel, just
'w nd6_debug 1' and 'c' should do the trick - then see what shows up
in /var/log/messages.

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