Automatic source routing
ml at sekil.fr
Tue Sep 24 16:41:56 CEST 2013
Le 24 sept. 2013 à 16:08, Phil Mayers a écrit :
> On 24/09/13 13:30, Emmanuel Thierry wrote:
>> The problem is really annoying if you want to use autoconfiguration
>> in a multihoming scenario without the need for an external daemon.
>> But maybe i missed a sysctl flag or something like that.
> Maybe, maybe not. What system are you using to manage your networking - for example, are you on a recent desktop distro using NetworkManager, which behaves badly in this case?
I'd say "of course" not. ;) Nothing which could have an effect on the network stack. This is a development system (running on debian wheezy) with only base tools.
The goal is to have a platform which acts has a multihomed router (with forwarding enabled) but automatically configures its addresses and default routers from RAs (accept_ra set to 2). For this test, the forwarding were disabled in order to limit potential side effects. I also tested with different kernels, it seams the linux kernel always behave like this...
>> Do you confirm the problem ? Does someone knows any automatic (i mean
>> in-kernel) solution to source route packets through the right
>> interface ?
> What does your ipv6 routing table look like? ("ip -6 route")
root at debian:~# ip -6 r
fd01::/64 dev eth1 proto kernel metric 256 expires 80554sec
fd02::/64 dev eth2 proto kernel metric 256 expires 80557sec
fd08:2::/64 dev eth3 proto kernel metric 256
fe80::/64 dev eth0 proto kernel metric 256
fe80::/64 dev eth1 proto kernel metric 256
fe80::/64 dev eth2 proto kernel metric 256
fe80::/64 dev eth3 proto kernel metric 256
default via fe80::5054:ff:fe00:132 dev eth1 proto ra metric 1024 expires 25sec
default via fe80::5054:ff:fe00:142 dev eth2 proto ra metric 1024 expires 23sec
As you can see there are the two default routes, received both from the router on eth1 and eth2, and no alternative rule or routing table.
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