What Is a Firewall and Different Types of Firewalls
Posted on Friday, July 31, 2020 and filed under Articles
A firewall is a cybersecurity system that serves the purpose of filtering traffic on a network. Its chief goal is to obstruct harmful traffic requests while allowing genuine traffic to pass through. You can also use firewalls to separate network nodes from internal and external traffic sources. Firewalls may take the form of hardware, software, or cloud-based systems.
The different types of firewalls include:
Packet Filtering Firewalls
These firewalls are deployed on the routers that connect the internal network to the internet. You can only implement Packet Filtering Firewalls on the Network layer of the OSI (Open System Interconnection) model.
Circuit Level Gateway Firewalls
These work at the Session layer of the OSI model and monitor sessions such as Transmission Control Protocol 3-way handshake to check whether a requested connection is genuine or not.
Application Level Gateway Firewalls
Application-level gateway firewalls, such as a Proxy Server, operate on the application layer of the OSI model and provide firm protection for a particular Application Layer Protocol.
Stateful Multilayer Inspection Firewall
This firewall is a combination of all the firewalls mentioned above. It can evaluate packets on Application Layer and filter packets at the Network layer, making use of Access Control Lists.