How do I know if a site is using DDoS protection provided by a third party service?

Question

DDoS Protection

There are many services like Cloudflare, F5, incapsula and many others that provide DDoS protection for websites. How do you know if a site (any arbitrary site) uses such protection? Not always the domain of the DDoS service will be mapped to the NS of the site domain. I know that in some cases changes are made to the A and CNAME records of the domain (and what will happen in the CNAME is unknown). In what ways is DDoS protection from third-party services "fastened" to the site, and how to determine it?

Answer 1

Hello.
There are several ways.
1. If the site is protected, then most often they change the DNS servers to ns of the company providing protection.
2. If a dedicated server or VDS is being protected, then create a GRE or IPIP tunnel.
How to determine? - Here 50% to 50%
The easiest way to see the DNS history. There will be a history of domain records, including adding ns servers or records protecting companies. 50/50 because DNS doesn't always have a history