Avira Premium Internet Security contains a firewall program that blocks unwanted or dangerous Internet traffic from your computer. The firewall has default settings to allow safe traffic to pass to your computer, e.g., Hypertext Transfer Protocol (HTTP) on port 80 or File Transfer Protocol (FTP) on port 21, but blocks unknown or unauthorized ports. You can add a firewall rule to configure Avira to allow open ports for applications that are not covered by the default settings. Warnings Writer Bio
