[ale] IPv6 - disabling RA client when static IPv6 address is configured?

[mike at trausch.us (Michael Trausch)]

On Sat, Apr 24, 2010 at 9:04 PM, Chris Woodfield <rekoil at semihuman.com> wrote:
> I have my home network sitting behind an Airport Extreme with an IPv6 tunnel set up to a local ISP who's doing an IPv6 rollout, complete with my own /64 allocation. For the server, I went ahead and configured a static IPv6 address (/etc/network/interfaces on an Ubuntu install), but I'm also running RA on the AE for the benefit of my other machines.
>
> What I've noticed is that in addition to the static, the server still configures a global IPv6 address from the route advertisements:
>
> eth0 ? ? ?Link encap:Ethernet ?HWaddr 00:26:18:95:5d:bd
> ? ? ? ? ?inet addr:192.168.0.41 ?Bcast:192.168.0.255 ?Mask:255.255.255.0
> ? ? ? ? ?inet6 addr: 2607:f080:207:201::41/64 Scope:Global
> ? ? ? ? ?inet6 addr: 2607:f080:207:201:226:18ff:fe95:5dbd/64 Scope:Global
> ? ? ? ? ?inet6 addr: fe80::226:18ff:fe95:5dbd/64 Scope:Link
>
> I also wind up with two default gateways, one being the AE's static IPv6 address and the other its link-local:
>
> ::/0 ? ? ? ? ? ? ? ? ? ? ? ? ? 2607:f080:207:201::1 ? ? ? UG ? 1 ? 0 ?2621 eth0
> ::/0 ? ? ? ? ? ? ? ? ? ? ? ? ? fe80::21b:63ff:fef4:69f7 ? UGDAe 1024 0 ? ? 0 eth0
>
> Not sure why, but this causes local transfers over IPv6 to go verrry slooowwwwwly. When I delete the RA-configured address and gateway, things go back to normal...until both get repopulated a few minutes later when the AE sends out the next RA packet.
>
> Anyone have any ideas how to stop the autoconfiguration of IPv6 addresses when I'm doing it statically already?

Yes, disable the automatic configuration on the interface:

net.ipv6.conf.all.autoconf = 0
net.ipv6.conf.default.autoconf = 0

Put that in /etc/sysctl.conf to prevent IPv6 autoconfiguration after
the next time you reboot, and then:

$ for i in all default eth0; do sudo sysctl -w
net.ipv6.conf.${i}.autoconf=0; done

To disable it without rebooting.  Then you can remove the
autoconfigured address and it will not reappear.  Don't forget to
delete the extra routing information as well.

   -- Mike