Anddos nginx server module
Anddos is a nginx server plugin. It aims to differentiate clients by their behaviour (requests sent on server). The basic approach is classifying clients based on server's response to their requests. It can define patterns of “normal” client and divide normal/not normal clients and block them if needed. More detailed information can be found at https://github.com/aufi/anddos/wiki. I wrote it as a diploma thesis in the end of my university studies. Unfortunately, the project is discontinued and it does not fully work.