Re: [Doh] DNS Camel thoughts: TC and message size

Petr Špaček <petr.spacek@nic.cz> Wed, 06 June 2018 14:21 UTC

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Subject: Re: [Doh] DNS Camel thoughts: TC and message size
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On 6.6.2018 16:18, Tony Finch wrote:
> bert hubert <bert.hubert@powerdns.com>; wrote:
>>
>> So, the DNS Camel has a suggestion. Specify that DNS messages carried over
>> DOH can be up to 65536 bytes large and note that truncation should be
>> handled as if the response was carried over TCP/53.
>>
>> Effectively this means that a TC response over DOH is almost always useless,
>> but this is no loss of functionality since it did not work over TCP/IP
>> either. We've not made anything worse here.
>>
>> And in general this is what I hope that DOH will restrict itself to: provide
>> access to the DNS protocol over HTTPS and not change DNS itself.
> 
> Full agreement, and with the rest of your message. Thanks for writing it
> so that I didn't have to!
> 
> I think the semantics of a DNS message transported over HTTPS should be
> the same as for DNS-over-TCP, wrt truncation, EDNS buffer sizes, and so
> forth.

I totally agree with Bert and Tony, thank you for an excelent summary!

-- 
Petr Špaček  @  CZ.NIC