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

Tue Aug 25 15:49:23 UTC 2020

> William Herrin
> Sent: Tuesday, August 25, 2020 4:20 PM
> 
> On Tue, Aug 25, 2020 at 4:15 AM Douglas Fischer
> <fischerdouglas at 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