Types of Firewalls in Network Security
Nowadays, protecting our sensitive data from unauthorized and unwanted sources has become a significant challenge. There are numerous tools available that can provide various levels of security and aid in the protection of private information stored in any system. A ‘firewall’ is a network security mechanism that protects our systems and data against unauthorized access.
In this blog, we will provide an overview of what a firewall is, the various types of firewalls in network security, and their significance.
What is Firewall?
A firewall is a cybersecurity device or software application that filters network traffic. A firewall acts as a traffic cop at your computer’s port. A fundamental purpose of a firewall is to create a barrier that separates an internal network from incoming external traffic to block malicious traffic requests and data packets, such as malware and hacking while allowing legitimate traffic to pass through. A firewall enables only the traffic that has been configured to accept, like IP addresses. It differentiates between legitimate and malicious traffic and allows or blocks specific data packets based on predefined security rules.
Why do we need a Firewall?
A firewall is a necessary component of a company’s overall cybersecurity strategy. Most computers have an in-built firewall, but it isn’t always the best option for security. What can a firewall do to keep us safe?
- It guards computers against unauthorized access.
- It blocks unwanted content.
- It provides a secure network when multiple people interact at the same time.
- It prevents ransomware from spreading.
- It protects private information, such as online banking credentials.
Types of Firewalls
Here are the list of different types of firewalls:
1.Packet-filtering firewall :Â A Packet-filtering firewall filters all incoming and outgoing network packets. It tests them based on a set of rules that include IP address, IP protocol, port number, and other aspects of the packet. If the packet passes the test, the firewall allows it to proceed to its destination and rejects those that do not pass it.
Benefits of a Packet-filtering firewall
- Quick and inexpensive
- Oldest and most fundamental firewall
- Protection against advanced threats is limited
2. Stateful Multi-Layer Inspection (SMLI): Stateful Multi-Layer Inspection firewall employs packet inspection technology and TCP handshake verification to provide protection. These firewalls, also known as dynamic packet filtering, examine each network packet to determine whether it belongs to an existing TCP or another network session. The SMLI firewall creates a state table to store session information like source and destination IP address, port number, destination port number, etc.
Benefits of Stateful inspection firewall
- Reduced traffic flow
- High-level protection
- Consumed significant system resources
- Provides extensive logging capabilities
3. Stateless firewall :Â Stateless firewalls monitor the network traffic and analyze each data packet’s source, destination, and other details to determine whether a threat is present. These firewalls can recognize packet state and TCP connection stages, integrate encryption, and other essential updates.
Benefits of Stateless firewall
- Less complex
- Easy to implement
- Fast performance delivery
- Performs effectively in heavy traffic situations
4. Application-level gateway (Proxy firewall) :Â Application-level firewall, also called Proxy firewall, is used to protect data at the application level. It protects from potential internet hackers by not disclosing our computer’s identity (IP address). Proxy firewalls analyze the context and content of data packets and compare them to a set of previously defined rules using stateful and deep packet inspection. They either permit or reject a package based on the outcome. Because this firewall checks the payload of received data packets, it is much slower than a packet-filtering firewall.
Benefits of Application-level firewall
- Safest firewall
- Deep packet inspection
- Significant slowdowns
- Safeguard resource identity and location
5. Circuit-level gateway :Â Circuit-level gateway validates established Transmission Control Protocol (TCP) connections. These firewalls typically operate at the OSI model’s session level, verifying Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) connections and sessions. These firewalls are implemented as security software or as pre-installed firewalls. Like packet filtering firewalls, these firewalls do not examine the actual data packet but observe the information about the transaction.
Benefits of Circuit-level gateway
- Simple and inexpensive
- A single form of protection is insufficient
- Setup and management are simple
6. Next-Generation Firewall (NGFW):Â The most common type of firewall available today is the Next-Generation Firewall (NGFW), which provides higher security levels than packet-filtering and stateful inspection firewalls. An NGFW is a deep-packet inspection firewall with additional features such as application awareness and control, integrated intrusion prevention, advanced visibility of their network, and cloud-delivered threat intelligence. This type of firewall is typically defined as a security device that combines the features and functionalities of multiple firewalls. NGFW monitors the entire data transaction, including packet headers, contents, and sources.
Benefits of Next-Generation Firewall
- Block malware
- Recognizing Advanced Persistent Threats (APTs)
- Less expensive
- Financially beneficial
7. Cloud firewall : A Cloud firewall, also known as FaaS (firewall-as-service), is a firewall that is designed using a cloud solution for network protection. Third-party vendors typically manage and operate cloud firewalls on the internet, and they are configured based on the requirements. Today, most businesses use cloud firewalls to protect their private networks or overall cloud infrastructure.
Benefits of Cloud firewall
- Unified security policy
- Flexible deployment
- Simplified deployment and maintenance
- Improved scalability
- Automatic updates
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