XF 2.1 Unable to register when block international IP

[Quangvinhvnz]

Hello Xenforo team

My website is under attacked ddos so I proceeded to block all IPs from international. But after implementing this method, the domestic user fails to register or the registration page does not transfer to the registration notice page. (eg :/register/complete) After I unblocked the international IP, the registration process is normal again! Is this a mistake , error from my server or ixenforo tracks registration from abroad?
I used xenforo 2.1

 

[Snog]

If you're blocking a full CIDR such as x.x.x.x/8 that's a very bad idea. Subnet masks in that range (/16, /17, etc.) could belong to different countries.

And with the use of proxies today, blocking full ranges is also a bad idea.

 

[Quangvinhvnz]

If you're blocking a full CIDR such as x.x.x.x/8 that's a very bad idea. Subnet masks in that range (/16, /17, etc.) could belong to different countries.

And with the use of proxies today, blocking full ranges is also a bad idea.

i see, thanks for your comment.
I wonder why when i unblocking international IPs, then account registration function of the website works normally? Does xenforo is tracking the registration process? Or my server has mistake !
My server used centos 7, Directadmin