Types of Firewalls
Firewalls are a critical part of every network, protecting businesses and individuals from cyberattacks. They are constantly working to check data packets based on predefined rules, stopping threats that bypass other security measures. Firewalls also help support compliance with regulatory frameworks.
Firewalls can be implemented as hardware (like the Linksys and Netgear firewall devices you can buy at electronics stores) or software, such as the Windows Firewall Control Panel or the Unix/Linux iptables. Firewalls are typically configured with a set of policies that specify what data packets should be accepted, denied, or dropped. These policies are based on a combination of factors including the source and destination IP address, port number, and protocol type.
A more advanced firewall type, called stateful inspection, analyzes the behavior of data packets and network connections, cataloging patterns over time to detect emerging attacks. However, if the firewall isn’t properly configured to identify and filter malicious packets based on their context, attackers can trick it into letting harmful connections through by using known attack techniques like exploiting network rules.
Application-level gateways, aka proxy firewalls, act as intermediaries between internal systems and external networks by handling communication requests on behalf of the network user. This allows for greater security, but introduces latency and may impact performance. This class of firewall can also perform deep packet inspection, examining the contents of each data packet to look for signs of malware or other threats.