---
title: "What are firewalls?"  
description: "What are firewalls?"  
author: "Tarun Gautam"  
published: 2017-11-14  
canonical: https://answers.mindstick.com/qa/30572/what-are-firewalls  
category: "technology"  
reading_time: 1 minute  

---

# What are firewalls?

What are firewalls?

## Answers

### Answer by Sangsaptak Pal

A [firewall](https://en.wikipedia.org/wiki/Firewall_(computing)) is a network security device that is either a hardware or software which monitors all the incoming and outgoing traffic. Based on a defined set of security rules it accepts, rejects or drops the specific traffic. The modes are as follows :

- Accept : Accepts and allows the traffic in the network
- Reject : Blocks the traffic but replies with an unreachable error
- Drop : Blocks the traffic with no reply

Firewall, in other words, serves as the boundary between the internal secured networks and outside untrusted network such as the Internet.

![What are firewalls?](https://media.geeksforgeeks.org/wp-content/uploads/introduction-to-firewall-1.png)

Firewalls are of two types :

- Host-based firewall : It protects each and every individual nodes from attacks and unauthorized access
- Network-based firewall : It protects the internal network

Categorization of firewall based on generation :

- First generation - Packet Filtering Firewall
- Second generation : Stateful Inspection Firewall
- Third generation : Application Layer Firewall
- Next Generation Firewalls (NGFW)

In Windows, already a firewall is installed that is Windows Firewall.

![What are firewalls?](https://cdn.windowsreport.com/wp-content/uploads/2017/09/Firewall-Windows-1.jpg)\


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Original Source: https://answers.mindstick.com/qa/30572/what-are-firewalls

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