Chapter 13: Firewalls & Filters

Access Control List (ACL)

A list of rules used by firewalls to allow or deny traffic based on IP addresses, ports, or protocols.

application layer firewall

A firewall that filters traffic based on specific applications or services, such as web browsers or email.

blacklist

A list of restricted entities (IP addresses, websites, etc.) that are blocked by a firewall or filter.

blocking

The action of preventing specific types of data or connections from entering or leaving a network.

content filter

A tool that blocks or restricts access to certain types of online content, like adult sites or social media.

Deep Packet Inspection (DPI)

An advanced method of filtering that examines the contents of data packets to detect harmful or unauthorized material.

Denial-of-Service (DoS) Attack

An attempt to make a system or network unavailable by overwhelming it with traffic; often stopped by firewalls.

firewall

A security system that monitors and controls incoming and outgoing network traffic, acting as a barrier between trusted and untrusted networks.

hardware firewall

A physical device that protects a network by filtering traffic between the internet and internal systems.

inbound traffic

Data coming into a network or device from the outside.

IP address

A unique identifier assigned to a device on a network.

IP address filtering

A method that allows or blocks traffic based on the source or destination IP address.

malware filter

A filter that scans and blocks malicious software from entering a network or system.

network firewall

A firewall that protects an entire network by controlling access to and from all connected devices.

outbound traffic

Data being sent from a device or network to an outside destination.

packet

A small unit of data transmitted over a network.

parental controls

Settings that limit children's access to certain content, websites, or apps, often using filters.

port

A communication endpoint used by applications to send and receive data over a network.

port blocking

Preventing data from using specific communication ports, commonly used to block unauthorized services.

proxy server

An intermediary system that filters requests between users and the internet to enhance privacy and security.

ruleset

A collection of rules a firewall uses to determine what traffic to allow or block.

spam filter

A program that detects and blocks unwanted or harmful email messages.

stateful inspection

A firewall method that monitors the state of active connections and makes decisions based on the traffic's context.

whitelist

A list of trusted entities (IP addresses, websites, etc.) that are allowed through a firewall or filter.