The stupidity of trying to "fix" DHCPv6

Iljitsch van Beijnum iljitsch at
Fri Jun 10 15:49:51 UTC 2011

On 10 jun 2011, at 17:26, Leo Bicknell wrote:

>> 1. No longer the fait sharing that comes from RA-learned gateway addresses

> I proport that VRRPv6 is a superior solution to have redundant
> gateways than using RA's to broadcast both and let the host choose.

It's not about redundancy, it's about misconfiguration. You can't misconfigure an RA to provide the wrong gateway address because the gateway address is the source address of the packet.

> My guess is that most networks that use DHCPv6 will disable RA's
> completely on the routers.

Haven't you been paying attention?

One of my main points is that you can't do that for many years to come, becasue CURRENT hosts require them. It took us 8 years to get from the publication of the DHCPv6 RFC to the deployment of DHCPv6 in all big operating systems. What's the point of doing all kinds of stuff now just so you can turn off RAs in 2019? By that time the switches will have all the necessary options so the problem is moot.

> I'm going to assume operators aren't going to do such stupid things.

Not sure what universe you live in. In mine, if you give people a way to misconfigure, a good number of them will do so. And a small but vocal group will defend their misconfiguration and claim that this is really the best way to run their network, all the while complaining to their vendors and the IETF about the problems that this creates and that those need to be solved.

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