Comodo Firewall is a personal firewall that filters ingoing and outgoing traffic on your computer. It alerts you of any applications that attempts to connect to the Internet and allows you to permanently or temporarily allow or block the connection. Advanced users can customize the application and TCP/IP rules based on IP address, protocol and destination port, however this is not required unless you have a reason to customize the rules. In addition to application behavior and network connections, Comodo Firewall also monitors components (dll files etc.) that initiate network connections, as well as parent processes and modifications to executables (checksum verification). Other features include attack prevention (port scanning, flooding), adjustable security levels, trusted networks, activity log and more. Comodo Firewall is easy to use for novice users, but includes enough flexibility via custom rule settings that allow advanced users to tweak it for their needs. The program requires a free registration after 30 days.