What is a firewall?
A firewall is a device, software, or system that prevents unauthorised access to or from a private network. This can be achieved through the use of an Internet firewall or proxy server and packet filtering. It’s like having a door between you and the outside world. It helps protect against unauthorised access, particularly over the Internet.
Types of firewall
- Network-based firewalls: Network-based firewalls are hardware devices that sit on your network and analyse traffic as it passes through. They can be either software or hardware, but in any case, they’re the most common type of firewall in use today.
- Host-based firewalls: Host-based firewalls are installed on individual systems within a network to protect them from external access by filtering all incoming and outgoing packets.
- Personal firewalls are software applications that run on your computer or device and protect you from unwanted internet traffic by monitoring incoming requests and blocking anything that doesn’t belong there.
- Proxy server firewalls act as intermediaries between users and the web, funnelling web requests through an intermediary before reaching their intended destination so that they’re able to enforce restrictions made by an administrator(s).
Most Commonly used Firewalls:
Network-based firewall
A network-based firewall is a software or hardware combination that sits in the network and monitors all incoming and outgoing traffic. It can be implemented on a router, switch, or firewall. These are often referred to as “packet filters.”
A basic network-based firewall will allow you to manage who accesses your network from the outside world. This type of firewall will block incoming traffic from unauthorised IP addresses unless otherwise specified by an administrator for legitimate use (i.e., employees accessing internal resources). As part of this process it blocks spoofed IP addresses, which are used when attackers try to make their computers look like they’re coming from a trusted source (like Google).
Host-based firewall
A host-based firewall is software that controls the flow of information between computers on a network. Host-based firewalls are usually included with operating systems and can be configured to allow or deny certain types of network traffic.
Web application firewalls (WAFs)
Web application firewalls (WAFs) are used to protect websites and web applications from attacks. WAFs can be used to protect against SQL injection, cross-site scripting, and other common attacks.
WAFs can be installed on the server or on the client. If you have a public-facing website that accepts user input, it’s recommended that you install a WAF on your web server so that all requests are filtered before they reach your database. If there is no filter in place before users enter data into your database, then an attacker could potentially access sensitive information such as customer credit card numbers or passwords by exploiting flaws in your application code.
A firewall is inherently less secure than a router, and thus an additional layer of security is needed.
A firewall is inherently less secure than a router and therefore an additional layer of security is needed. A router only determines the best path for traffic to flow between networks, but it does not inspect or filter incoming or outgoing traffic based on its source, destination and port. For example, a network administrator might want to allow all traffic from the Sales department on one side of the firewall to go through without inspection, but block all other traffic at this location.
A firewall’s purpose is to protect your network from outside threats by inspecting data before it gets into your network while providing access only when needed via specific ports (e.g., 80/8080)
Conclusion
A firewall is an additional layer of security that helps protect your network from attacks and intrusions. It can be installed on devices such as computers, routers, switches, printers and phones to protect against unauthorised access. A firewall can be set up either at the network level or at the host level depending on your needs. If you want more control over what happens within your network then a host based firewall would be ideal because it works on each individual device rather than just blocking traffic coming in or going out like an external firewall would do.
