Firewall-Configuration-and-Common-Misconfigurations.md

@@ -5,12 +5,21 @@ Firewalls are a key component of a secure network. At a basic level, a firewall
 When configuring a firewall for a network, the administrator will set a variety of *rules*, or policies that determine what traffic should be permitted into or blocked from the network. There are multiple ways that firewall rules can help filter traffic, and the following three methods are the most common: packet filtering firewalls, application-level firewalls, and stateful inspection firewalls. Other types of firewalls include unified threat management firewalls, next-generation firewalls, and virtual firewalls.   
 
 ## Packet Filtering Firewalls
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+![Packet Filtering Firewall](https://content.iospress.com/media/aac/2016/7-2-3/aac-7-2-3-aac008/aac-7-aac008-g001.jpg?width=755)
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 *Packet filtering* involves checking incoming traffic against a series of filters. This traffic enters the network as a collection of packets, or segments of data. Based on the filtering rules, acceptable packets will be permitted to enter the system, and all other packets will be rejected.
 
-## Application-Level Firewalls
+## Application-Layer Firewalls
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+![Application-Layer Firewall](https://networkencyclopedia.com/wp-content/uploads/2019/08/application-layer-proxy.jpg)
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 *Proxy service* is when the firewall acts as an in-between for a client server and the Internet. In this configuration, the firewall requests and retrieves the information from the Internet and processes it before it enters the protected network. This places the majority of the risk on the remote proxy device, rather than the device inside the network.
 
 ## Stateful Inspection Firewalls
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+![Stateful Inspection Firewall](https://www.illumio.com/sites/default/files/2020-05/statefulFWblog_figure3_v1_1400x712.jpg)
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 *Stateful inspection* is an up-and-coming innovation in firewall technology. It builds upon the concept of packet filtering in hopes of making it more efficient. Rather than checking the entire packet contents, the firewall only inspects specific parts of a packet against a collection of trusted data. Additionally, stateful inspection also monitors outgoing traffic, or information moving from the network to the Internet. The dynamic nature of stateful firewalls allows for certain filtering rules to be changed or ignored in specific circumstances.
 
 ## Why do we Use Firewalls?