Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds

Fernando Gont <> Thu, 31 October 2019 19:44 UTC

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To: Ted Lemon <>, Philip Homburg <>
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From: Fernando Gont <>
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Date: Thu, 31 Oct 2019 16:41:28 -0300
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Subject: Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds
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On 27/10/19 14:14, Ted Lemon wrote:
> On Oct 27, 2019, at 11:05 AM, Philip Homburg <
> <>> wrote:
>> If you think that this is an important thing to fix, feel free to 
>> talk about it. But why in this discussion? SEND doesn't do anything for
>> flash renumbering. From an operational point of view, RA-guard is much
>> more attractive then SEND. So it is not clear to me that there is any
>> need for SEND. But I could be wrong. In any case, if there is a need
>> to discuss SEND we could do that separately.
> I think you missed my point.  You can’t do flash renumbering by
> advertising a prefix with a valid lifetime of zero, because that will be
> ignored by hosts.   If it were not ignored by hosts, it would be a very
> effective DoS vector. 

As someone that has played a lot with ND-based DoS vectors, I should say
that you trust RAs, or you don't. If you do, all bets are off. ("sudo
apt-get install ipv6toolkit;man ra6" and you'll get examples of a bunch
of other DoS attacks that an attacker can perform).

>From an attacker's point of view, you just need one that works.

Fernando Gont
SI6 Networks
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