What is a Firewall?
Imagine going to a nightclub in Las Vegas and waiting in a long line to get in. There is a large bouncer at the entrance checking everyone’s IDs and making sure they don’t have any weapons that could cause harm to the people already inside the club. Well, that bouncer at the front entrance of the club is acting as the firewall. He’s a barrier between everything inside and anything harmful outside.
A firewall on a computer network is a security device that monitors incoming and outgoing network traffic. A firewall, much like a bouncer, permits or blocks packets of data based on a set of security rules, establishing a barrier between your internal network and incoming traffic from external sources. Not only does a firewall block unwanted traffic, but it can also help block malicious software from infecting your computer. This article can help you learn what firewalls do and determine the level of protection that will help keep your computer and the data on it safe and secure.
What does a firewall do?
Similar to our nightclub bouncer scenario above, a firewall acts as a gatekeeper. Firewalls represent the first line of defense in home network security. However, a firewall shouldn’t be the only thing securing your home network. It’s crucial to make sure all of your internet-enabled devices have the latest operating system, web browsers, and security software installed on them. It is a smart idea to secure your wireless router too. This includes changing the name and password of your router to something only you know, reviewing your security options, and setting up a guest network for visitors. Your operating system and your security software usually come with a pre-installed firewall. It’s a good idea to make sure those features are turned on. Also, make sure your security settings are configured to run updates automatically.
How does a firewall work?
A firewall is a very intricate piece of your network security. It carefully analyzes incoming traffic based on pre-established rules and filters traffic coming from unsecured or suspicious sources to prevent malicious attacks. A firewall only welcomes those incoming connections that it has been configured to accept. Firewalls guard traffic at a computer’s entry point called ports, which is where information is exchanged with external devices. Every network location has an address, called an IP address.
IP addresses are important because they identify a computer or source, just like your postal address identifies where you live. Try to imagine an IP address as a hotel, and port numbers as rooms within the hotel. Only trusted guests (source addresses) are allowed to enter the hotel (destination address). Then it’s further filtered so that guests within the hotel are only allowed to access their rooms (destination ports). The owner of the hotel is the only person with a master key or access to any room (any port), while all guests are only allowed access to their room (specific ports).
What are different types of firewalls?
One of the most asked questions regarding firewalls is if a firewall is a hardware or software. The answer is both. A software firewall is a program installed on each computer and regulates traffic through port numbers and applications. A physical firewall is a piece of equipment installed between your network and gateway. The most common type of firewall is a packet-filtering firewall. The packet-filtering firewall examines packets of data and forbids them from passing through if they don’t match an established security protocol.
Packet-filtering firewalls are split into two types: stateless firewalls and stateful firewalls. Stateless firewalls analyze packets separately from one another and lack context, rendering them easy targets for hackers. Stateful firewalls collect information about earlier passed packets and are therefore deemed much more secure. While packet-filtering firewalls can be helpful, they only provide very basic protection and can be very limited. If a malicious request came from a trusted IP address, the firewall would have no way of knowing. Next-generation firewalls and proxy firewalls are more designed to identify those threats.
What happens if I don’t have a firewall?
Even if you’re being extra careful when you’re online, you still need a firewall. Practicing safe computer and internet use like not clicking on unknown links or attachments, using only trustworthy websites, and having strong passwords is good. But does that make your network safe enough? Unfortunately, not. If you use the internet, it’s smart to have a firewall in place as cyber threats are common and progressing. Here are the most common risks of not having a firewall.
- Open access - Without a firewall, you’re receiving every connection into your network from anyone. You have no way to identify incoming threats, leaving your devices at risk of malicious attacks.
- Lost or compromised data - Not having a firewall leaves your devices exposed, allowing hackers to gain control over your computer or network. Cybercriminals could delete your data or even hold it for ransom, demanding payment to get it back.
- Network crashes - Without a firewall, a hacker could potentially shut down your network. Getting it operating again, and trying to recover your stored data, consists of valuable time and money.
Firewalls are an important part of network security, especially when different types of firewalls work together in providing a blanket of protection. Firewalls can help keep your network, computer, and data safe and secure.