IPS/IDS with SELK

[BrateloSlava]

It not blocks traffic based on invalid TCP, UDP, whatever - it blocks traffic from e.g. known bad hosts automatically.
Also it does deep inspection and stops any malicous traffic which you in general would allow on a firewall level - e.g. TCP/443 for you webserver.
If a bad bot would like to try some SQL injections it will recognise it and blocks the host.

Read this - Help! Create script for possible future security Ddos