(usagi-users 01886) Re: switch problems with multicast ethernet packets?

[Pekka Savola <pekkas@xxxxxxxxxx>]

On Tue, 8 Oct 2002, Hadmut Danisch wrote:
> On Tue, Oct 08, 2002 at 08:49:21AM +0300, Pekka Savola wrote:
> > > 
> > > Has anyone else experienced such problems?
> > 
> > Yes.
> > 
> 
> This problem could have severe implications on the use of
> ipv6. 
> 
> I can remember to already have had problems with ethernet
> multicast in a different context. 1-2 years ago I was 
> performing some experiments to configure Nokia firewalls
> and a Linux machine for high availability with VRRP, which
> also makes use of ethernet multicast. 
> 
> Beside the fact, that the experiments were given up because
> of software bugs in the available software releases, 
> ethernet multicast turned out to be problematic, because
> some (many?) cheap ethernet adapters don't handle these
> addresses properly and must be set into promiscuous mode
> to receive those packets. Promiscuous mode is something
> you don't want to have in a production network.
> 
> 
> Therefore I'd suggest to have a switch in 
> 
>   /proc/sys/net/ipv6/conf/*/
> 
> which allows to make the ipv6 code use simple
> broadcasts ff:ff:ff:ff:ff:ff instead of multicasts.
> It's not ipv6 conforming, but it's a workaround.

One could theoretically work around this by creating static node -> 
mac-address mapping with /sbin/ip (personally, done with BSD)..

-- 
Pekka Savola                 "Tell me of difficulties surmounted,
Netcore Oy                   not those you stumble over and fall"
Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords