[radvd-devel-l] Router advertisement and forwarding on client side?

Pekka Savola pekkas at netcore.fi
Mon Mar 19 12:50:33 EST 2007

On Mon, 19 Mar 2007, vincent.trucmuche wrote:
>> hasn't worked.  User-friedliness :-)
> Could we imagine a simple warning? A sentence like:
> "You are running radvd while not forwarding... are you sure
> this is what you want?"

This is how it's happening if radvd is run in debug mode.

>> Please elaborate.  Would radvd be run on that configuration server? 
>> What information would radvd provide?  Or where would radvd be 
>> used?
> There many cases where one want to separate the router from
> the configuration services so we can imagine a LAN with one or
> several default routers (thanks to IPv6 anycast adresses ;) )
> and one or several DHCP and radvd machines in order to give
> configuration (subnet, NTP server...)..

You didn't tell which information would be distributed with radvd. 
What radvd configuration would you use? Which ND options would be 

Giving a concrete example might also help.  Why should information be 
distributed with radvd instead of the default router?

Just Prefix Information options?  Are you suggesting that radvd will 
be able to start in non-forwarding mode if the configuration includes 
'AdvDefaultLifetime 0' and no more-specific route statements? If yes, 
are you willing to create a patch that does this cleanly?

> I don't think. DHCP-PD is used to delegate to a router a
> prefix for "the other side" of this router. For instance, a
> CPE could get a prefix for its LAN side. But, even if RFC 3633
> (DHCP-PD) talk about "delegating router" and "requesting
> router" it's not obvious that "delegating router" is also the
> default gateway. So the question remains... if RA are trashed
> by my CPE, how could it learn it's default route?

As far as I understand, DHCP-PD will set up the routing for the 
delegated prefix (on the upstream side) and the default route (on the 
downstream WAN interface).

Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings

More information about the radvd-devel-l mailing list