Cloudflare
The following is only needed if you are using Cloudflare as a proxy service, If you use it as DNS only you do not need to do any of this.
Modify the following line : https://github.com/C0nw0nk/Nginx-Lua-Anti-DDoS/blob/master/lua/anti_ddos_challenge.lua#L65
To this :
local remote_addr = "auto"
So Cloudflare allows you to Cache pages on their CDN the header status in requests will say
CF-Cache-Status : HIT
If you use page rules to Cache pages of your site you need to modify this line.
https://github.com/C0nw0nk/Nginx-Lua-Anti-DDoS/blob/master/lua/anti_ddos_challenge.lua#L85
To this :
local javascript_REQUEST_TYPE = 2
Because Cloudflare caches GET requests it will cache the Anti-DDoS page output instead of what you intend to be Cached so to fix it we make it a POST request since Cloudflare does not Cache those.