nanog mailing list archives

RE: TCP and UDP Port 0 - Should an ISP or ITP Block it?


From: <adamv0025 () netconsultings com>
Date: Tue, 25 Aug 2020 16:49:23 +0100

William Herrin
Sent: Tuesday, August 25, 2020 4:20 PM

On Tue, Aug 25, 2020 at 4:15 AM Douglas Fischer
<fischerdouglas () gmail com> wrote:
a) Should an ISP block that Kind of traffic?

Hi Douglas,

Generally speaking the answer is NO, You should not presume that your
understanding of your customers' data traffic is sufficiently complete or
correct to make blocking decisions for them.

Agree, but there are less invasive options as well like rate limiting or comb rate-limiting (i.e. rate-limiter per 
address range).    


b) Should a Transit Provider block that Kind of traffic?

Preemptively? Never. If I found my business transit provider was doing this,
I'd treat it as a breach of contract.

Agree, but again one can still do proactive rate limit based on historical data (to address the hit and run type of 
attacks -that exploit the reactive application of filters).  

adam


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