Mandatory Firewall
All Campus Stations must have firewall configured and maintained,
ConfigServer Security and Firewall
The current default firewall on Linux is ConfigServer Security and Firewall (CSF)
Shorewall
Shorewall is a simple file wall that is no longer maintained but still being used extensively (especially behind CSF - inside system containers and virtual machines)
Easywall
Easywall is an easy to use firewall that is no longer maintained but has been popular in limited situations where maximum ease of use is required.