The answer is “it depends”. What are you trying to accomplish? Are you trying to detect and surgically mitigate every DDoS attack? If so, you will need a good DDoS attack detection and mitigation solution and a team of people to run it or a 3rd party company that can do this for you. Do you want a cheap solution? There are open source projects that can detect DDoS attacks and generate RTBHs, flowspec rules, and inline filters that can block the traffic (eg. https://fastnetmon.com). Also, RTBHs can usually be advertised upstream (and to UTRS https://www.team-cymru.com/utrs.html) to reduce the amount of attack traffic that the victim network receives. Some ISPs just do the RTBH to the customer’s IP when there’s a DDoS and then force the customer to get another IP via DHCP, etc. -Rich From: NANOG Email List <nanog-bounces@nanog.org> on behalf of NANOG list <nanog@nanog.org> Reply-To: Shawn L <shawnl@up.net> Date: Thursday, April 23, 2020 at 3:39 PM To: NANOG list <nanog@nanog.org> Subject: Re: Best way to get foreign ISPs to shut down DDoS reflectors? This brings up an interesting question -- what is "good DDoS protection" on an ISP scale? Apart from having enough bandwidth to weather the attack and having upstream providers attempt to filter it for you/ -----Original Message----- From: "Bottiger" <bottiger10@gmail.com> Sent: Thursday, April 23, 2020 5:30pm To: "Siyuan Miao" <aveline@misaka.io> Cc: "North American Network Operators' Group" <nanog@nanog.org> Subject: Re: Best way to get foreign ISPs to shut down DDoS reflectors? We are unable to upgrade our bandwidth in those areas. There are no providers within our budget there at the moment. Surely there must be some way to get them to respond. On Thu, Apr 23, 2020 at 2:23 PM Siyuan Miao <aveline@misaka.io<mailto:aveline@misaka.io>> wrote: It won't work. Get a good DDoS protection and forget about it. On Fri, Apr 24, 2020 at 5:17 AM Bottiger <bottiger10@gmail.com<mailto:bottiger10@gmail.com>> wrote: Is there a guide on how to get foreign ISPs to shut down reflectors used in DDoS attacks? I've tried sending emails listed under abuse contacts for their regional registries. Either there is none listed, the email is full, email does not exist, or they do not reply. Same results when sending to whatever other email they have listed. Example Networks: CLARO S.A. Telefonica China Telecom Korea Telecom E-MAIL CONFIDENTIALITY NOTICE: The contents of this e-mail message and any attachments are intended solely for the addressee(s) and may contain confidential and/or legally privileged information. If you are not the intended recipient of this message or if this message has been addressed to you in error, please immediately alert the sender by reply e-mail and then delete this message and any attachments. If you are not the intended recipient, you are notified that any use, dissemination, distribution, copying, or storage of this message or any attachment is strictly prohibited.