@Filboxz i have the same problem. They should put a time intervals for every unsuccesful attempt and increase the security to alphanumeric code. Also the one guessing my voucher code is a vivo user as well.

I have the same problem. And I block them manually. I only unblock them when they try to legally connect with a valid voucher and complain that they can't connect to the wifi.

I just told them (a lie), that his/her device was automatically get locked after trying to guess invalid voucher codes.

On your screenshot, the one's with android-(then some numbers) are easy to manually block as those numbers are unique to each device.

The problem is, those vivo-(then some numbers) are not unique. They can represent different devices, not just one specific device. Same with iPhones. huawei and oppo phones.

@Filboxz 

TP Link please update your controller
 

 Temporary Block client who are Guessing a voucher code

need aditional security feature 

*5 attemp guessing a code will automatically block for 1 hour

*show client mac address on log = many user here in my area have same phone so i need to determine who user is that. need aditional info of client