No ISP is in the business of filtering traffic unless the client pays the hefty fee since someone still has to tank the attack. I also don’t think there is destination prefix IP filtering in flowspec, which could seriously cause problems. From: NANOG <nanog-bounces@nanog.org> On Behalf Of Baldur Norddahl Sent: Saturday, September 01, 2018 5:18 PM To: nanog@nanog.org Subject: Re: automatic rtbh trigger using flow data fre. 31. aug. 2018 17.16 skrev Hugo Slabbert <hugo@slabnet.com<mailto:hugo@slabnet.com>>: I would love an upstream that accepts flowspec routes to get granular about drops and to basically push "stateless ACLs" upstream. _keeps dreaming_ We just need a signal to drop UDP for a prefix. The same as RTBH but only for UDP. This would prevent all volumetric attacks without the end user being cut off completely. Besides from some games, VPN and VoIP, they would have an almost completely normal internet experience. DNS would go through the ISP servers and only be affected if the user is using a third party service. Regards Baldur