What is a Firewall?

A firewall is a network security device that monitors incoming and outgoing data from your network and allows or denies the data to reach its end destination depending on rules configured by the entity responsible for managing the firewall. Its purpose is to block malicious traffic like viruses, malware, and hackers, and is the first line of security defense for your network.

Firewalls can be physical devices, or a software program running on servers or workstations.

How does it work?

Firewalls, both physical and software, analyze incoming and outgoing data, using rules created and enabled by the firewall provider, your IT service, or other software that engages with the firewall. By filtering this data, the firewall can determine if traffic is legitimate and if it should be allowed through to its end destination.

For example, if content filtering is enabled, the firewall will identify traffic coming from an unauthorized website—usually via IP addresses—and block access, notifying the end user. You may have experienced this in your web browser: you attempted to visit a site, and instead got a warning that the site is not allowed or that it’s unsafe to visit.

Firewalls protect more than just web browser traffic, however. Your network has “ports” or specific locations that data will try to access depending on the type of data it is. A very common one is a port that is open for VoIP phone traffic. Your firewall would have a rule set that only traffic coming from the VoIP provider is allowed to enter this port, but all other traffic will be denied.

Why does it matter?

Network security is essential to maintaining a healthy network, and ensuring that your work isn’t interrupted by viruses, malware—and that your data remains secure and inaccessible to bad actors.

By utilizing a firewall as the first line of defense in your web of security, you are able to block malicious traffic before it enters your network, and ensure that people and devices are only able to access exactly what they need to and no more.

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