The BotFilter plugin is a protective plug-in against bots for your server, it is built into BungeeCord (a plug-in that allows you to connect several servers), the plug-in will allow you to check incoming players quite efficiently for several parameters, including forcing them to enter captcha (verification code from the picture).
At the moment there are 3 types of protection, this is a drop check, a captcha test, and a captcha and fall test at the same time.
Dowonlad: http://rubukkit.org/threads/an…apchej-1-8-1-15-2.137038/