A lot of users are asking how to block certain country IP blocks and lock down some services. Tired of spam, server daemon scanning, brutce force attacks, service floods and so on....
we have made a neat script that can generate IP tables to block countries like Taiwan, Russia, Korea... .. just specify the port and protocol and that's it!
http://blacklist.linuxadmin.org/
enjoy!
ps. all commands are safe for your current firewall (don't forget to run script generated commands after you start your current firewall/packet filter)