Emergency DOS or DDOS stopping script
If you are under a DOS or DDOS attack and running out of your mind or don’t know what to do, use this script to get ride of this panic situation.
DoS or DDoS is an attempt to make a victim website unavailable by creating hundreds to hundreds thousands of established connections that overflow victim resources and makes a website unavailable to the genuine users/visitors.
Short and useful slide that definite this script can be view on slideshare
You can run script to mitigate a low level ddos attack some how while and can stop DOS attack completely. This script is available under GPL license from the author.
How to mitigate DoS or DDoS attack?
Stop or flush other rules for now :
service apf stop iptables -F wget http://www.hackersgarage.com/wp-content/uploads/2011/08/antiDDoS.txt mv antiDDoS.txt antiDDoS.sh chmod u+x antiDDoS.sh ./antiDDoS.sh
Some other useful commands to analyze the type of attacks :
netstat -antp | grep ESTABLISHED netstat -antp | grep -i sync netstat --help
Source: hackersgarage.com