I can't figure out how to install a basic firewall such as rc.firewall or Firewall-Easy etc, on DSL . I don't mind what type or brand of firewall it is. The reason why I can't install the firewall is because I can't perform basic function such as update my DSL distribution with the command sudo apt-get update . I searched on google how to install rc.firewall damn small linux and many people can actually install a firewall on DSL but they don't explain how they installed the firewall..  How can I install any simple firewall ? 
How to install a basic firewall on DamnSmallLinux?
debian