# Fundamentals of Firewalls

- [What is a Firewall](/network-security/courses/isci-cnss-course/fundamentals-of-firewalls/what-is-a-firewall.md)
- [Firewall Types](/network-security/courses/isci-cnss-course/fundamentals-of-firewalls/firewall-types.md)
- [Firewall Implementation](/network-security/courses/isci-cnss-course/fundamentals-of-firewalls/firewall-implementation.md)
- [Proxy Servers](/network-security/courses/isci-cnss-course/fundamentals-of-firewalls/proxy-servers.md)
- [Windows Firewalls](/network-security/courses/isci-cnss-course/fundamentals-of-firewalls/windows-firewalls.md)
- [Linux Firewalls](/network-security/courses/isci-cnss-course/fundamentals-of-firewalls/linux-firewalls.md)