What computing appliance blocks and filters unwanted network traffic?

A computing appliance that blocks and filters unwanted network traffic is known as a Firewall. Firewalls serve as a security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. They can be hardware-based, software-based, or a combination of both, and are essential for protecting networks from unauthorized access, cyber threats, and other troubles.

Types of Firewalls:

1. Packet Filtering Firewall: Inspects packets and allows or blocks them based on predefined rules.
2. Stateful Inspection Firewall: Maintains track of active connections and makes decisions based on the context of traffic.
3. Proxy Firewall: Intercepts requests from clients, retrieves data from the web and then sends it back to the client, masking the client's IP address.
4. Next-Generation Firewall (NGFW): Combines traditional firewall capabilities with additional features like intrusion prevention, application awareness, and deep packet inspection.

Firewalls are crucial for safeguarding sensitive data and maintaining security compliance in organizations. They can be deployed at different layers of the network architecture to provide comprehensive protection.