Collection of Linux Scripts for firewall, security, alerts, monitoring, etc… 1. check_syn_flood.rb Will check if there are more than 40 SYN_REC TCP streams from the same IP. Then it will block with iptables, inserting at top of chain the offending IP. such as: /sbin/iptables -I INPUT -s 123.1.1.1 -j DROP Works on Linux and OSX