Re: IPv6 on NetBSD 8

[Greg Troxel <gdt%lexort.com@localhost>]

Jan Danielsson <jan.m.danielsson%gmail.com@localhost> writes:

>    I have a vague memory of having read that IPv6 autoconfiguration has
> changed in NetBSD 8.  Something along the line of "rtadvd is dead, now
> dhcpcd is the way to go".  Am I remembering correctly?  If so; has
> anyone written a migration guide?

What you said isn't right - rtadvd is the router part.  As I understand
things:

* running rtadvd (or using quagga) on the router, to *advertise* a
  prefix and default router, remains the standard approach

* In NetBSD < 8, for a very long time, stateless autoconfiguration
  was done by setting ip6mode=autohost in rc.conf, and that set
  net.inet6.ip6.accept_rtadv = 1
  which caused the kernel to process Router Advertisements and create v6
  addresses using stateless autoconfiguration, when such RAs arrived.

  In addition, one could run rtsol (once) to send a solicitation, or
  rtsold to send them periodically.

* dhcpcd does IPv6 stateless autoconfiguration (with privacy extensions)
  by default (well, with the default config file at least).   This is
  essentially the same mechanism as the kernel RA listener and rtsold,
  but as I understand it with more care about correctness (and less use
  of kernel code).  Plus, it implements the privacy extensions, which
  allow stable addresses which cannot be matched to MAC addresses.

I think in NetBSD 8 you have two options:

* leave ip6mode=autohost in your rc.conf.  The in-kernel listener will
  run.  No Router Solicitations will be sent.  It's unclear what happens
  if you do this and run dhcpcd at the same time.  I do not recommend
  this.

* drop ip6mode=autohost from rc.conf, so that the default of host
  applies.  On any interface you want a v6 automatic address, run
  dhcpcd.  This should just work and you should have useful logs in
  /var/log/messages if not.  


So basically those last 4 lines are the migration guide.