Sure! Here is an SEO-friendly HTML answer for the Tech Support category interview question "Can you explain how a firewall works and why it is important for network security?":

```html

How Firewalls Work and Importance for Network Security

A firewall is a network security device that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It acts as a barrier between a trusted internal network and untrusted external networks, such as the internet.

Firewalls can be hardware-based or software-based and use a combination of technologies like packet filtering, proxy service, and stateful inspection to determine whether to allow or block traffic.

Firewalls are important for network security as they help prevent unauthorized access to a network, protect against malware and other cyber threats, and ensure the confidentiality, integrity, and availability of data. By setting up and configuring firewalls properly, organizations can enhance their overall network security posture.

```

This HTML content provides a clear and concise explanation of how firewalls work and why they are important for network security, which can help improve search engine visibility for the topic.