Re: [DNSOP] drop udp to stop DDOS?

Jim Reid <jim@rfc1035.com> Sat, 01 October 2016 15:50 UTC

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From: Jim Reid <jim@rfc1035.com>
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Date: Sat, 1 Oct 2016 16:50:37 +0100
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To: "A. Schulze" <sca@andreasschulze.de>
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Subject: Re: [DNSOP] drop udp to stop DDOS?
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> On 1 Oct 2016, at 16:36, A. Schulze <sca@andreasschulze.de> wrote:
> 
>> Could we eliminate the DDoS threat by just turning off UDP?
>> 
>> Recursive servers I understand probably have to keep accepting them, but authoritative servers are only intended for recursive servers to query, so would it be safe to just drop port 53 UDP requests?
> 
> are there any experiences/opinions on that?

Quite probably. They will be very unhappy ones.

The OP hasn’t yet figured out which port number and transport resolving servers use when they query authoritative servers.