What is a Firewall?
Firewall is a piece of hardware or software that monitors data packets (small bits of information sent between systems) and blocks malicious traffic, allowing only legitimate to enter your network. Often considered one of the foundational best practices for network security, firewalls are an essential tool to protect your business from cyberattacks.
In the early days of the modern internet, system administrators discovered that their networks were vulnerable to savvy third-parties who could sniff out incoming and outgoing data, steal sensitive information, or even gain access to the company network itself. To prevent this from happening, a new solution was needed — hence, the firewall was born.
When a firewall reads a packet of data, it compares it to its ruleset and decides whether to allow or deny the package. Generally speaking, these rules are based on multiple aspects of the packet data such as its source/destination IP address and ports used, its content and application associations, and more.
Ideally, these rules should be written by someone who understands the business processes and security needs of an organization. That’s why most off-the-shelf firewall products come with preconfigured rulesets – they’re designed to minimize setup time and reduce mistakes and deployment risks. They also help meet industry standard compliance guidelines like segmenting enterprise networks into corresponding security levels, which is an important best practice for optimizing security and reducing risk.