Re: High latency for IPv6 on netbsd-8

[Robert Elz <kre%munnari.OZ.AU@localhost>]

Just guessing, but this sounds to me like the "prohibiit sending from 
tentative addresses" BS that was added a while ago.

I'd suspect that it goes something like this ...

host boots, configures itself link-local addresses, and starts DaD
on them - addesses are tentative.

rtsol (v7) or dhcpcd (v8) starts, and sends a RS to request a
RA from the router.   In v7 that is just sent.  In v8 it is not, as
DaD isn't finished yet.

RS's don't get ack'd, the RA is not that, but even if the sender
decides to send another after not seeing a RA fairly soon, it might
still be within the DaD period.

The v7 host gets the RA, configures global v6 addresses, and all
works, the v8 host does not (quickly).

Routers send RAs periodically - every 10 minutes is a common config,
so eventually a RA appears, the v8 host configures its v6 addrs (finally)
and all is OK (the actual delay will vary of course, depending upon where
in the router's time sequence of regular RA sending the host boots).

To see if this guess is likely enough to be raised to be a hypothesis, do
two things...

First, soon after the boot, ping the router's link local address.   Since LL
(v6) addresses tend to be obnoxious things, it would be best to have a
script pre-prepared, and tested, for this in advance.

If that works (give it at least a second or two after boot - by the time you
can log in should be OK, but don't automate it in rc.local or anything), and
a ping6 of a global v6 address does not (nb: have the address calculatted
in advance, so it cannot be a DNS issue, and use -n on the pings - always...)
then this is a clue.

Then add

	net.inet6.ip6.dad_count=0

to /etc/sysctl.conf and reboot, and try again.   If the global v6 ping works this 
time, (and the LL ping both times) then this is likely to be the problem.

On the other hand if a global v6 ping to an address works, and one to a
hostname does not, then that would be evidence of DNS issues, and we
would need to look in a different direction.

kre

ps: I hope you are on the list, as gmail almost always rejects mail from me.