Re: [renum] [apps-discuss] Last Call: <draft-ietf-6renum-static-problem-02.txt> (Problem Statement for Renumbering IPv6 Hosts with Static Addresses) to Informational RFC

Brian E Carpenter <> Fri, 14 December 2012 08:01 UTC

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Date: Fri, 14 Dec 2012 08:02:13 +0000
From: Brian E Carpenter <>
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Subject: Re: [renum] [apps-discuss] Last Call: <draft-ietf-6renum-static-problem-02.txt> (Problem Statement for Renumbering IPv6 Hosts with Static Addresses) to Informational RFC
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> The server part relies on DHCPv6 and DNS for configuration management.  In my humble opinion, that's a recipe for service outage.

In my world, DHCP and DNS have been mission critical for twenty years.

   Brian Carpenter

On 13/12/2012 22:22, SM wrote:
> At 07:25 28-11-2012, The IESG wrote:
>> The IESG has received a request from the IPv6 Site Renumbering WG
>> (6renum) to consider the following document:
>> - 'Problem Statement for Renumbering IPv6 Hosts with Static Addresses'
>>   <draft-ietf-6renum-static-problem-02.txt> as Informational RFC
> These comments are after the Last Call.  As such I am ok if they are
> ignored.  There is a Cc to apps-discuss in case anyone is interested to
> comment about the application perspective.
> I am aware that renumbering is difficult.  I have read about the claim
> that "addresses are stable over long periods of time" in RFC 6250.  The
> Introduction Section of the draft mentions that:
>   "Static addresses may be configured automatically, for example by
>    stateful DHCPv6."
> It's fine to assign IP addresses to printers through DHCPv6.  The
> printer is a one-function device and it usually isn't critical.  I
> wouldn't use DHCPv6 for servers to be on the safe side.  If I had to
> choose between walking to the server to be able to access it when things
> go wrong and pushing an IP configuration manually, I would choose the
> former as it would have a lower impact on service availability.  Note
> that the server may be running multiple services which could interact
> with each other.
> In Section 2.3:
>   "However, it is very widespread operational practice that servers have
>    static IP addresses."
>   "Such server addresses can be managed centrally even if they are
>    static, by using DHCPv6 in stateful mode, and by generating both
>    DHCPv6 data and DNS data from a common configuration database using a
>    suitable configuration tool."
> This draft argues for DHCPv6 as the solution to make renumbering
> easier.  The draft seems to focus more on the client perspective where
> DHCPv6 (or SLAAC) is a worthwhile alternative for address assignment.  
> There's more to a server than assigning an IP address to the host.  If I
> configure a "Listen" address for an application and there is a DNS
> failure, the application does not start.  The problem statement (Section
> 4) mentions among other things printers and desktops.  The server part
> relies on DHCPv6 and DNS for configuration management.  In my humble
> opinion, that's a recipe for service outage.
> Regards,
> -sm
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