From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Adrian Moreno" <adrian_linux@gmx.com>
Date: Wed, 09 Oct 2013 13:20:37 +0000
Subject: Fw: IPv6 Dynamic gateways in separate routing tables
Message-Id: <20131009132038.302570@gmx.com>
List-Id: <lartc.vger.kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 8bit
To: lartc@vger.kernel.org

Hi all,

I have a multihomed system (very similar to the one described in LARTC HowTo Section 4.2. Routing for multiple uplinks/providers) with IPv6 addresses.
 
I want to create a routing table per interface to be able to route the traffic depending on the source address using IPv6 addresses and dynamic gateways.
How do I set the default gateway to be dynamic in a separate routing table?
 
My current configuration is:
    IF_1: Interface 1
    SUBNET_1: the subnet connected to Interface 1
    IPv6_1: IPv6 address configured on Interface 1
    T_1: Routing table for Interface 1
 
    IF_2: Interface 2
    SUBNET_2: the subnet connected to Interface 2 
    IPv6_2: IPv6 address configured on Interface 2
    T_2: Routing table for Interface 2
 
Configuration:
    ip -6 route add $SUBNET_1 dev $IF_1 table $T_1
    ip -6 rule add from $IPv6_1 table $T_1
 
I am clearly missing one route, that should look like:
    ip -6 route add default via <GATEWAY_1> tab $T_1
How should I set this route to use the dynamically obtained gateway?
 
The dynamic gateways are listed in the "default" routing table as:
    % ip -6 route show default
    default via DYNAMIC_GWv6_1 dev IF_1 proto kernel metric ....
    default via DYNAMIC_GWv6_2 dev IF_2 proto kernel metric ....
 
The order in which these routes are listed is arbitrary (restarting /etc/init.d/networking re-shuffles them).
Is there a way to ensure that a packet being sent from IPv6_1 goes out via the correct gateway (DYNAMIC_GWv6_1) and interface (IF_1)?
 
Many thanks in advance for any help.
 
Adrian