Direct SYN-flood attack mitigation with Cloudflare

Hi everyone in the Cloudflare community!

I’ve just joined Cloudflare to solve my problem with SYN-flooding, setting my webserver under pressure for several days by now. My own attempts to mitigate it with iptables rules helped only for some time and I decided to use Clouflare for help.

My server is on a separate hosting and I changed NS names to Cloudflare ones, so that my domain resolves by Cloudflare. The issues with SYN-flooding remain.
Maybe this question sounds stupid, but how does Cloudflare help with attack mitigation, if packets go to a particular IP address? The server is still on the same IP and whatever DNS changes I do, it will remain there.

SYN Flood traffic through Cloudflare shouldn’t even reach your server:

As you suspect, they’re targeting you directly, which is why you should set up a firewall at your host to block anything that doesn’t come from the list at IP Ranges


This totally makes sense. I’ve restricted the rules only for these IPs and the problem is gone.
Thank you so much for your prompt response!

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