Exploring Firewalls

One of the primary methods of controlling traffic in and out of a network is with a firewall. Firewalls filter traffic using different techniques. Some of the basic types of firewalls are as follows:

Firewalls are also covered in Microsoft Windows Networking Essentials (Wiley, 2011), which covers exam 98-366.

  • Packet-filtering (stateless)
  • Stateful-filtering
  • Content-filtering
  • Application-layer-filtering

Advanced firewalls can combine all of the filtering methods in a single firewall.

A packet-filtering firewall filters packets based on IP addresses, ports, and some protocols. If you want to allow traffic through a firewall from only specific computers, you can create rules using these computers’ IP addresses. Similarly, ...

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