Re: problem configuring squeeze

[Bjørn Mork <bjorn@mork.no>]

Eugen Leitl <eugen@leitl.org> writes:

> What worked for me (from /etc/network/interfaces ):
>
> # WAN IPv6 from 2a01:4f8:7d:300::/56
> iface eth0 inet6 static
> address 2a01:4f8:7d:300::2
> gateway 2a01:4f8:7d:300::1
> netmask 64
> # Disable autoconf
> post-up echo 0 > /proc/sys/net/ipv6/conf/default/accept_ra
> post-up echo 0 > /proc/sys/net/ipv6/conf/all/accept_ra
> post-up echo 0 > /proc/sys/net/ipv6/conf/$IFACE/accept_ra
> post-up echo 0 > /proc/sys/net/ipv6/conf/default/autoconf
> post-up echo 0 > /proc/sys/net/ipv6/conf/all/autoconf
> post-up echo 0 > /proc/sys/net/ipv6/conf/$IFACE/autoconf


Doing 

      pre-up sysctl -w net.ipv6.conf.$IFACE.accept_ra=0

or, if you want to keep the RA genereated default route:

      pre-up sysctl -w net.ipv6.conf.$IFACE.autoconf=0

should be more than enough.  Either way, you do need to do this
*pre*-up, as the kernel otherwise will send a router solicit message and
may receive an answer before the post-up commands are run.

>> > Kernel IPv6 routing table
>> > Destination                    Next Hop                   Flag Met Ref Use If
>> > 2a01:198:200::/64              ::                         UAe  256 0     3 eth0
>> > 2a01:4f8:7d:300::/56           ::                         U    256 0     1 eth0
>> 
>> IMO the prefix length for any local prefix should always be /64. The
>> purpose of a /56 prefix is to be divided into multiple /64 prefixes.

Yes.

And the whole /56 should also be terminated in a null route by doing
something like

   ip route add unreachable  2a01:4f8:7d:300::/56

or you may cause a routing loop which can be used to DoS your upstream
link.


Bjørn