Different Types of Firewalls
Firewalls analyze network traffic based on rules and allow only legitimate connections into the private network.
Without a firewall, any malicious user or bot could gain access to your system and steal personal information or compromise critical systems. This type of threat is known as a cyberattack.
There are different types of firewalls, each with its own features and functionality. The right type of firewall is critical to a successful cybersecurity strategy.
Packet filtering firewalls monitor network packets at a relatively low level of the TCP/IP protocol stack and only allow them to pass through if they meet the established rule set based on Internet Protocol (IP) addresses and ports. These devices perform better than similar devices that do application layer inspection, which can allow unwanted applications or malware to pass through the firewall.
Circuit-level gateways work at a higher layer of the Open Systems Interconnection (OSI) model to monitor established Transmission Control Protocol (TCP) sessions, keeping track of which TCP connections are active and what they’re doing. These firewalls are similar to packet filtering firewalls but are less resource-intensive and have a higher security rating.
Stateful inspection firewalls also filter packets at multiple layers of the OSI model, examining each packet to determine whether it’s part of an established TCP or other session, and ensuring that only trusted sources are involved. These devices provide more security than packet filtering or circuit monitoring alone but can impact network performance.
Next-generation firewalls (NGFW) have some of the same features as packet filtering and stateful inspection firewalls, but they also offer more comprehensive protection for private networks. They can also incorporate additional features such as intrusion detection and prevention, denial of service attack protection, and session monitoring.