[radvd-devel-l] Base6Interface concerns

Ludwig Nussel ludwig.nussel at suse.de
Fri May 6 04:31:06 EDT 2011


I'm wondering about the intention of the Base6Interface feature. I think it
could be useful in a setup I have for my dial-up line. I guess the way it's
implemented is hard to use in practice though.
On dsl1 my provider advertises a /64 prefix. It's actually network 0000 in
an /48 prefix though (the /48 is actually static in my case but it could
change on every dial in in the future too).
Now if the host connected to dsl1 acts as a host it would assign itself an
address in the 0000 network of the /48 prefix. By specifying Base6Interface
dsl1 on eth0 I could advertise the same /64 prefix in my LAN. However, the net
is already used as transit net between me and the provider. So I'd have to
choose e.g. 0001 for advertising in my LAN. The current implementation doesn't
allow that though. Some option to specify the base prefix would be needed.
Something like

	prefix 0:0:0:0001::/64
		Base6Interface dsl1;
		Base6InterfacePrefixLen 48;

Linux only recently gained the ability to run in "hybrid mode", ie accept RA's
even if in router mode. Before it woudn't even assign an address to dsl1 so
radvd woudn't find an addess in the first place. I guess radvd needs to listen
for RAs itself on the Base6Interface.
Also, what happens if the interface goes down? radvd would have to
somehow invalidate the prefix.


 (o_   Ludwig Nussel
 V_/_  http://www.suse.de/
SUSE LINUX Products GmbH, GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer, HRB 16746 (AG Nürnberg) 

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