[dns-operations] DNS Flag Day 2020 will become effective on 2020-10-01

[Petr Špaček]

Hi Orange-san,

On 09. 09. 20 7:00, Yasuhiro Orange Morishita / 森下泰宏 wrote:
> Hi Petr-san,
> 
> I tested some auth servers and resolvers by online checker in the
> official website.
> 
> But I feel that both of them display "GO" even if EDNS buffer size is
> not set to 1232.  Is this by design?

This is fine as long as all the authoritative servers work over DNS-over-TCP and respect EDNS buffer size sent by resolvers.

The reason is that the effective EDNS buffer size is the minimal value from (client, server) pair. Consequently, once resolvers update their defaults, the change will become effective without any changes on the auth side.

Lower EDNS buffer size might force fallback to TCP if auths are sending longer answers - that's why the web tester is checking availability of DNS-over-TCP.

I hope it helps.

If you can point to a section on https://dnsflagday.net/2020/ which should contain this answer I will be happy to add it there.

Have a nice day!
Petr Špaček  @  CZ.NIC



> 
> -- Orange
> 
> From: Petr Špaček <petr.spacek at nic.cz>
> Subject: [dns-operations] DNS Flag Day 2020 will become effective on 2020-10-01
> Date: Tue, 8 Sep 2020 12:04:39 +0200
> 
>> Dear DNS people.
>>
>> We are happy to announce next step for DNS Flag Day 2020.
>>
>> Latest measurements indicate that practical breakage caused by the proposed change is tiny [1]. In other words we can conclude that the Internet is ready for the change.
>>
>> The long delayed DNS Flag Day will become effective on 2020-10-01 (October 1st 2020)!
>>
>> Detailed information including test tools and technical description of the change can be found at https://dnsflagday.net/2020/ .
>>
>> For questions please use dns-operations at lists.dns-oarc.net mailing list.
>>
>> [1] https://github.com/dns-violations/dnsflagday/issues/139#issuecomment-673489183
>>
>> -- 
>> Petr Špaček  @  CZ.NIC