Re: rtadvd and bridging

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Tue, Nov 01, 2011 at 10:00:41AM -0400, Greg Troxel wrote:
> 
> Steven Bellovin <smb%cs.columbia.edu@localhost> writes:
> 
> > I have a NetBSD 5.1_STABLE box that is bridging three Ethernet interfaces;
> > it will also host a gif tunnel endpoint for v6 connectivity.  Which
> > interface should rtadvd run on?  gif0?  One of the Ethernets?  All
> > of the Ethernets?
> 
> Assuming the gif has outer IP addresses and inner IPv6 addresses (link
> local for ripng, real for bgp), it is highly unlikely to be appropriate
> to run rtadvd on it.   Is the gif for you to get connectivity, or to
> provide it?

Indeed, with this kind of configuration I often have to use ipf to
suppress IPv6 connectivity (including link-local) on the physical
interface carrying the gif or IPsec tunnel that brings me v6 connectivity.

Since both ends need to know the expected addressing for the gif already
it is probably not appropriate to run rtadvd over the gif even if in
fact you are using it to provide, rather than to get, connectivity.

-- 
Thor Lancelot Simon                                    tls%panix.com@localhost
  "All of my opinions are consistent, but I cannot present them all
   at once."    -Jean-Jacques Rousseau, On The Social Contract