A firewall is a network security device that monitors incoming and outgoing network traffic and permits or blocks data packets based on a set of security rules. Its purpose is to establish a barrier between your internal network and incoming traffic from external sources (such as the internet) to block malicious traffic such as viruses and hackers.
There are various types of firewalls in a computer network, which are as follows −
A packet filtering firewall is an essential type of firewall. It facilitates a management program that monitors web traffic and filters incoming packets based on configured security methods.
These firewalls are created to block network traffic IP protocols, an IP address, and a port number if a data packet does not connect to the established rule-set.
It is also known as Proxy Firewalls. Proxies are mainly used to control or monitor outbound traffic. Some application proxies cache the data requested.
This lower bandwidth requirement decreases the access time for the following user to access the same data. It also gives unquestionable evidence of what was transferred.
Circuit-level gateways are another type of firewall that can easily configure to allow or block traffic without significant computing resources.
These types of firewalls typically operate at the OSI model’s session-level by verifying TCP (Transmission Control Protocol) connections and sessions. Circuit-level gateways are designed to ensure that the regular sessions are protected.
These work by filtering traffic moving by a network by the filtering is specified by the applications or traffic methods and the ports they are created.
Stateful multilayer inspection firewalls contain both packet inspection technology and TCP handshake verification. It can create SMLI firewalls better than packet-filtering firewalls or circuit-level gateways. These types of firewalls keep track of the status of established connections.
It allows multiple devices with independent network addresses to connect to the internet using a single IP address, keeping individual IP addresses hidden.
Threat-focused NGFW contains all the features of a traditional NGFW. They can also support advanced threat detection and remediation. These types of firewalls can react against attacks quickly.
Whenever a firewall is created using a cloud solution, it is called a cloud firewall or FaaS (firewall-as-service). Cloud firewalls are supported and run on the Internet by third-party vendors.