What is the Difference between a Firewall and IDS?

Although computers have essentially become common household item these days, not many of use are aware of all the security requirements advised for our computer systems. Two common security items in popular use are firewalls, both software and hardware, and software intrusion dection systems or IDS.

To understand the difference between firewalls and IDS, imagine that you keep a lot of valuables in your home and wish to protect them. What do you do? You set barriers such as gates at the entrance and also install home security systems like security alarms. We can relate locked gates to firewalls and security alarms to intrusion detection systems.

What is a Firewall?

A firewall is a computer program that monitors the system and blocks the entry of viruses and other unwanted programs. Put simply, it regulates the connection between your system and the Internet. Firewalls are of two types: hardware and software. A hardware firewall is a piece of hardware that sits between your modem and the system. Often these are wired or wireless routers or broadband gateways. A software firewall is a piece of software installed in the system to protect your computer from unauthorized access or entry.

The diagram below will show you how a firewall works.

How a Firewall Works

Image from Privacy Canada

What does a firewall do?

• • A firewall blocks open ports through which an intruder can gain access to your system and the valuable data you have stored in it.
  • As all information passes through firewall, you can know what is happening in the network.
  • It allows you to create rules or set privileges for the type of traffic that can pass through the firewall in both directions.
  • It blocks malicious viruses from entering your system.

What is an Intrusion Detection System or IDS?

An Intrusion Detection System (IDS) is a software (application) or hardware (device) that monitors a system, network, or a database and analyzes them for signs of a possible violation of defined security policies.

What does IDS do?

• • Monitors the activities of the system and alerts the user of any intrusion
  • Adds integrity to your system and the infrastructure
  • Helps the system administrator to set up policies

What is the difference between a firewall and IDS?

Okay… we saw what firewall and IDS are and what they do, but what exactly is the difference between a firewall and IDS? A firewall monitors the system based on the rules that are set by the user and regulates the activity between the system and the Internet, and IDS monitors the system for unwanted entry and reports or alerts the same to the user.

Do you have a question of whether you require firewall or IDS to protect your system? If you ask me, I would say you require both firewall and IDS. Why? As said earlier, firewalls guard the front doors, but what will you do if there is an attack via the backdoor? Therefore, to protect the system from unwanted intrusions, it is always recommended to use firewalls in conjunction with Intrusion Detection Systems (IDS). THis is also why the majority of internet security systems comes with both firewall and IDS.