Different Types of Firewalls
Firewall is a cybersecurity device, available as computer hardware or software, that prevents attackers from accessing your private network or computers. A firewall creates a barrier between your system and outside data, examining each piece of information as it enters or exits your operating system to detect malicious activity. It can be one of the best tools in keeping your computer, network and data safe from cyberattacks.
Generally, different types of firewalls use varied methods to analyze and filter out incoming and outgoing data packets, including:
Packet Filtering – The firewall inspects each data packet on a relatively low level (network layer) for recognizable patterns of suspicious behavior. This method is usually quicker but does not detect the same range of cyberattacks as other types of firewalls.
Stateful Inspection – The firewall analyzes the flags set on each packet in order to determine what is being communicated between two systems. For example, packets with only the SYN flag are presumed to be a new connection while ACK and RST indicate a closed connection. The firewall can then compare these data packets to a state table to make decisions about whether or not to allow the packet through.
Proxy Firewalls – These type of firewalls are unique in that they combine both network layer inspection and stateful inspection in a single device. They also provide advanced security features like DNS protection, application-level inspection and threat management capabilities.