So specific to vbulletin I found in version 4.25 they had added support for reverse proxies to obtain the real client IP address.
In the config...

So now i wanted to talk specifically about how a firewall will stop DDOS attacks.
During my attacks i found that pretty much all solutions work...

I recently suffered massive and targeted DDOS attacks on my servers rendering them useless.
This is when i really discovered Cloudflare and Sucuri...

Hey Everyone,
I run two vbulletin forums of an adult nature so I will be discreet about them
One forum is still on VB 4.25 and working...