Re: nd6 change and rc.d/network_ipv6 -> rc.d/netif integration

Dag-Erling Smørgrav <des_at_des.no> wrote
  in <86my45vhlj.fsf_at_ds4.des.no>:

de> Hiroki Sato <hrs_at_FreeBSD.org> writes:
de> > John Hay <jhay_at_meraka.org.za> writes:
de> > > Is there a good reason why we still ship with ipv6 off by default?
de> > What do you mean by "off by default"?  I think IPv6 is not disabled by
de> > default with the patch.
de> 
de> % ident /usr/src/etc/defaults/rc.conf 
de> /usr/src/etc/defaults/rc.conf:
de>      $FreeBSD: head/etc/defaults/rc.conf 197619 2009-09-29 16:49:10Z dougb $
de> % grep ipv6_network_interfaces /usr/src/etc/defaults/rc.conf
de> ipv6_network_interfaces="none"	# List of IPv6 network interfaces
de> #ipv6_network_interfaces="ed0 ep0"	# Examples for router
de> % grep ipv6_prefer /usr/src/etc/defaults/rc.conf 
de> ipv6_prefer="NO"	# Use IPv6 when both IPv4 and IPv6 can be used
de> 
de> Does mean that IPv6 is disabled by default?  Who knows?  There is no
de> coherent explanation *anywhere* of what these variables mean, and
de> rc.conf(5) does not mention them at all.  In fact, the first hit for
de> "ipv6" in rc.conf(5) is this:
de> 
de>      ipv6_enable
de>                  (bool) Enable support for IPv6 networking.  Note that this
de>                  requires that the kernel has been compiled with options
de>                  INET6.

No, the rc.conf(5) has been updated in r197526:

     ipv6_enable
                 (bool) If the variable is ``YES'', ``inet6 accept_rtadv'' is
                 added to all of ifconfig_<interface>_ipv6 and the ipv6_prefer
                 is defined as ``YES''.

                 This variable is deprecated.  Use ipv6_prefer and
                 ifconfig_<interface>_ipv6.

and UPDATING also explains the relationship between the $ipv6_enable
and the other variables.

IMHO "Enabling (or disabling) IPv6" is not a correct expression for
$ipv6_enable and $ipv6_prefer.  If you use a kernel with "options
INET6" (GENERIC has it) IPv6 is enabled, and $ipv6_enable=NO in the
old releases does not disable the functionality.  It just controlled
whether $ipv6_* in rc.conf are ignored or not.

-- Hiroki