[dns-operations] Some DNSSEC trivia

[Florian Weimer]

* Lutz Donnerhacke:

> * Mark Andrews wrote:
>> 		Idiots with firewalls.
>>
>> 	* respond to queries from port 53.
>> 	* respond to queries from well know UDP malware source ports.
>
> Please add "4096 Byte EDNS0 UDP Queries".

As MUST or MUST NOT?  It's not clear to me if large UDP packet support
beyond the de-facto Internet MTU is a good idea due to the traffic
amplification issue.

I'd rather see that servers respond to 53/TCP in all cases.  That way,
a resolver which detects that it's under a spoofing attack can fall
back to TCP, hopefully relying on the somewhat stronger TCP sequence
numbers.

-- 
Florian Weimer                <fweimer at bfk.de>
BFK edv-consulting GmbH       http://www.bfk.de/
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