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

Ole Troan <otroan@employees.org> Mon, 28 October 2019 14:11 UTC

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From: Ole Troan <otroan@employees.org>
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Date: Mon, 28 Oct 2019 15:10:53 +0100
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To: Philip Homburg <pch-v6ops-9@u-1.phicoh.com>
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Subject: Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds
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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.

Cheers,
Ole