Re: [netmod] question regarding IPv6 address format / canonical

Ladislav Lhotka <lhotka@nic.cz> Mon, 10 December 2018 13:46 UTC

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From: Ladislav Lhotka <lhotka@nic.cz>
To: Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de>, Mikael Abrahamsson <swmike@swm.pp.se>
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Subject: Re: [netmod] question regarding IPv6 address format / canonical
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Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de>; writes:

> On Fri, Dec 07, 2018 at 09:51:53AM +0100, Mikael Abrahamsson wrote:
>> > 
>> > It is the value that the server (conceptually) uses internally. See sec. 9.1 in
>> > RFC 7950.
>> 
>> Ok, so if the server doesn't re-format and always uses string in the
>> canonical format, that's a clear bug?
>>
>
> Yes. How the server does things internally does not matter but
> comparisons must conceptually use the canonical format (and this is
> why it is so important to define the canonical representation in type
> definitions).

When we are at it: defining the canonical format for a derived type so
that it differs from the base type (as it is here) is problematic
because it is specified only in a description and tools thus cannot take
it into account automatically. So I expect problems like the one
reported by Mikael to be quite common - and if not for the IPv6 address,
then certainly for other derived types.

Lada

>
> /js
>
> -- 
> Juergen Schoenwaelder           Jacobs University Bremen gGmbH
> Phone: +49 421 200 3587         Campus Ring 1 | 28759 Bremen | Germany
> Fax:   +49 421 200 3103         <https://www.jacobs-university.de/>

-- 
Ladislav Lhotka
Head, CZ.NIC Labs
PGP Key ID: 0xB8F92B08A9F76C67