Re: 9.0-beta3 preferring ipv4 over ipv6 with ipv6_activate_all_interfaces="YES"

From: Hiroki Sato <hrs_at_FreeBSD.org>
Date: Mon, 17 Oct 2011 04:29:31 +0900 (JST)
Thomas Steen Rasmussen <thomas_at_gibfest.dk> wrote
  in <4E9AA874.5070403_at_gibfest.dk>:

th> On 14.10.2011 10:26, Thomas Steen Rasmussen wrote:
th> > On 14-10-2011 10:09, Hiroki Sato wrote:
th> >>  Thanks.  There is no problem with the source address selection.
th>
th> I don't understand this comment. I would say that I do
th> have problems with the source address selection -
th> otherwise it would be preferring ipv6, right ?

 I mean the address selection is working properly.  Your problem is
 because the default ipv6_prefer policy prefers IPv4 addresses when
 the source IPv6 addr is in 2002::/16, the destination IPv6 address is
 not in the same prefix, and IPv4 addresses can be used for the both.
 It is not a bug of the selection mechanism.

 The ipv6_prefer policy is defined in RFC 3484 2.1 and this policy
 chooses a src IPv6 addr in 2002::/16 only if the dest addr is also in
 the same prefix.  You can remove the special rule for 2002::/16 by
 putting the following lines as /etc/ip6addrctl.conf and reboot the
 system:

 ::1/128          50      0
 ::/0             40      1
 #2002::/16       30      2
 ::/96            20      3
 ::ffff:0:0/96    10      4

 By installing the above, IPv6 address will be preferred even if it is
 in 2002::/16.

 I am still not sure why there is a difference between 8.X and 9.X on
 your box because the code is almost the same.  I guess no policy was
 installed when you used an 8-stable system.

-- Hiroki

Received on Sun Oct 16 2011 - 17:30:20 UTC

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