HeatShield is a network firewall management service for Linux servers. A firewall configured by HeatShield prevents unauthorized access to services running on your servers, such as SSH and MySQL. Using HeatShield, you can easily restrict access to these services so that only IP addresses you trust are allowed to communicate with your servers.
Additionally, HeatShield dynamically updates your servers' firewalls to block IP addresses that have attempted brute force SSH login attacks on any of your servers.
via BetaList http://bitly.com/29pIgMv
by Robert Hughey (Google+)