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

Fernando Gont <> Fri, 01 November 2019 03:31 UTC

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To: Ole Troan <>, Philip Homburg <>
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From: Fernando Gont <>
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Date: Fri, 1 Nov 2019 00:31:10 -0300
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Subject: Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds
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On 28/10/19 11:10, Ole Troan wrote:
> Philip,
>>> No, the question is if there is any host stack + server software
>>> that deals with flash renumbering deployed.  And that is deployable
>>> without coding.
>> Flash renumbering is by and large not a server problem. If a request
>> reaches the server, then the server typically can reply. Any flow that
>> spans the renumbering event will be affected, but there are lots of 
>> other issues that also affect established flows.
>> If you renumber the network that contains mail servers, web servers,
>> xmpp servers, etc., then the servers don't really notice.
>> Of course, a renumbering event requires DNS to be updated, possibly changes
>> to firewalls, etc. But that is no different from a proper renumbering event.
> And this is something you have tested and verified works?
> For a set of typical open source packages?
> See Bjørn's message as well.
> And try to see what happens when you do this for a hidden primary DNS server...
> The world just isn't ready for flash renumbering of networks, likely not graceful renumbering either.
> There are not many sensible responses the end-users can come up with to a service provider with a network behaving this way, apart from isolating addressing. Aka NAT.

We did in fact propose several. (draft-gont-6man-slaac-renum).

It would be amusing for v6ops' response to this case that folks should
be doing NAT.

Fernando Gont
SI6 Networks
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