Firewalls can be divided into:
1. Stateful
A stateful firewall is a type of firewall that keeps track of the state of network connections passing through it. It is able to remember information about each connection, including the source and destination IP addresses, port numbers, and the status of the connection (open, closed, etc.).
With this information, a stateful firewall is able to make more informed decisions about what traffic to allow or block. It can also use this information to apply different rules to different types of traffic, such as allowing certain types of traffic while blocking others.
Stateful firewalls can also track the entire conversation of a network connection, as it happens. For example, it can track the start, middle, and end of a connection, it also can check and match the start of the connection with the end of the connection to make sure it’s not a spoofed connection.
Stateful firewalls are considered to be more advanced and more secure than stateless firewalls, which only examine individual packets of data without keeping track of the state of the connection.
2. Stateless
A stateless firewall is a type of firewall that makes decisions about traffic based solely on the individual packets of data, without keeping track of the state of the connection. It doesn’t keep any information about the network connections passing through it and it only checks the headers of the packets and it doesn’t keep any information about the conversation.
A stateless firewall only examines each packet based on a set of predefined rules, without considering the context of the connection. This means that it doesn’t take into account whether a packet is part of an established connection or if it’s a new connection. It only looks at the packet’s source and destination IP addresses, port numbers, and other header information.
Stateless firewalls can be simpler to configure and manage than stateful firewalls, but they are considered to be less advanced and less secure. Because stateless firewalls don’t track the state of the connection, they are unable to detect certain types of malicious traffic, such as spoofed connections.
Stateless firewalls are commonly used as the first line of defense in a network security architecture. They are often used in conjunction with other security measures, such as stateful firewalls, intrusion detection systems, and antivirus software, to provide a comprehensive defense against cyber threats.
3. Next Generation Firewall
A Next Generation Firewall (NGFW) is a type of firewall that provides advanced security features beyond traditional firewalls. NGFWs are designed to protect networks from a wide range of threats, including those that traditional firewalls may not be able to detect or block.
NGFWs typically include a combination of hardware and software components that work together to provide advanced security capabilities. These capabilities include:
- Stateful inspection: NGFWs keep track of the state of network connections passing through them, just like stateful firewalls, and can make more informed decisions about what traffic to allow or block.
- Application-layer inspection: NGFWs can examine and control access to specific applications and services, regardless of the port or protocol used.
- Intrusion prevention: NGFWs can detect and prevent a wide range of network attacks, including those that exploit vulnerabilities in specific applications or services.
- Advanced threat protection: NGFWs can use a combination of techniques, such as deep packet inspection, sandboxing, and machine learning, to detect and block advanced threats such as malware, ransomware, and APTs.
- Encryption and VPN: NGFWs can inspect and decrypt traffic that is encrypted using VPNs or other encryption protocols, and can also provide VPN services.
- Cloud and network integration: NGFWs can be integrated with other security products, such as cloud security, to provide a more comprehensive defense.
NGFWs can be deployed in different ways, such as in hardware appliances, virtual appliances, or as a service in the cloud. They can also be used in different parts of a network, such as at the perimeter, in the data center, or in the cloud.
NGFWs are considered to be more advanced and more secure than traditional firewalls, they are an essential component of any modern security infrastructure.