A firewall is a type of technology that enforces rules on the type of data that can be transmitted into or out of a particular computer system or IT network. It is an early line of defense against unauthorized access to sensitive computer systems.

Terms related to Firewall: Malware, Antivirus, Hacking. Breach, Vulnerability, Cybersecurity, Whitelist, Blacklist.

A firewall is an important part of any organization’s technology defenses. Firewalls work with other tools like antivirus software, security monitoring, and vulnerability testing to prevent unauthorized access, hacks, and attacks on systems and data. A firewall is an important “virtual barrier” that can eliminate, restrict, or reduce damage caused by unauthorized access.

Firewalls are build into many applications, devices, and systems, and typically exist as “firmware” or “software.”

Firewalls specifically assess “data packets” — information that is sent into and out of computer networks. They establish if these data packets, and the channels and routes they are using, meet certain predefined firewall rules. If they do not meet these rules, the data packets are rejected and cannot access the organization’s networks. If they do meet the rules, they are allowed through. Firewalls can also base these assessments around whitelists and blacklists.

Firewalls can have sophisticated, multi-step rules and can also dynamically adjust those rules based on other factors. Typical rules can include the protocol that the data packet is sent by, the ports that it is trying to access, the source of the data packet, the destination of the data packet, and several other parameters. In addition to filtering traffic, firewalls can also log and audit the traffic that is accepted and rejected by the firewall.

Firewalls can be installed on individual devices, in data centers, in the cloud, and elsewhere.

Firewall Resources from Crossmatch