What is a Firewall?

Firewalls are designed to block unauthorised traffic to your computer or network whilst filtering the incoming and outgoing network traffic using policies and rules that are set in place. A Firewall limits your network to exposure from outside cyber threats. When a firewall has defined rules, it can identify traffic that is hazardous to your network or safe, then based on that it will also define what to do with the intrusion such as blocking it.

Firewalls can be implemented using hardware, software or a hybrid of both.

Different types of Firewalls

The main function of any firewall is to filter data packets that come through. Depending on the firewall, depends on what happens to those data packets and whether they are authorised.

There are 5 types of firewalls:

• Packet filtering firewall – they operate where devices such as routers and switches work. They compare each packet received to a set criteria. The criteria could be based on IP addresses, packet type etc. Those deemed as a risk are blocked.
• Stateful inspection firewall examines each packet, but keeps track of whether or not that packet is part of an established TCP or other network session. This offers more security than either packet filtering or circuit monitoring but causes a greater toll on network performance.

1. Circuit-level gateway identifies malicious content and network protocol session initiation messages across the network, as they are established between the local and remote hosts to determine whether the session being initiated is legitimate and whether the remote system can be trusted. They don't inspect individual packets.

4.Application-level gateway (aka proxy firewall) combines some of the features of packet filtering firewalls with those of circuit-level gateways. They filter packets not only according to the service for which they are intended but also by certain other characteristics. While gateways that filter at the application layer provide considerable data security, they can dramatically affect network performance.

5.Next-generation firewall (NGFW) combines packet inspection with stateful inspection in addition to deep packet inspection, intrusion detection/prevention, malware filtering and antivirus. Unlike traditional firewalls, the next-gen firewall is aware of user roles, device types and app flows.

Benefits of a Firewall

• Monitors Traffic to identify any potential risks to your computer network.
• Blocks Trojans which are dangerous because they covertly transmit your information to unscrupulous people.
• Stops Hackers from using your computer to spread viruses.
• Stops Keyloggers from using your keystrokes to access and use your sensitive information.