Cloudflare is able to repel attacks without (Under Attack Mode) Checking your browser before accessing pages?

Question

DDoS Protection

Without Under Attack Mode, Checking your browser before accessing... 5 sec... the pre-page immediately crashes the server. Just Security Level: High instantly puts the server, apparently misses a lot.

Moreover, even ip from the white list constantly drives through this page.

Somewhat strange for their capabilities.

Answer 1

Depends on the type of attack. Banal UDP flood beat off without it. For high-level attacks without Under Attack Mode, it is more difficult, especially if at first it misses a lot, and the server does not pull.
If the channel is not clogged, and the problem is loading the server resources, this is to the server admin first of all, and not to the service protector. See what loads, optimize. Don't set any limits.
And CF boxes on default settings provide a very limited range of protection.