What It Is
A firewall sits between your server and the rest of the internet, deciding which connections are allowed through. It works like a building’s front desk that only lets in visitors on an approved list and turns away anyone trying a side door. Network firewalls usually make decisions based on where traffic comes from and which service, or port, it is trying to reach, such as the web server or the email server.
Why It Matters for Your Business
Every server on the internet is constantly probed by automated scanners looking for open doors. A properly configured firewall closes everything your website does not need, which removes a large share of easy targets. For a small business, this protection usually comes from the hosting company rather than from anything you install yourself. It is worth asking a host how their firewalls are managed and monitored.
Good to Know
A network firewall protects the server, but it does not understand what a web page request is trying to do. Attacks that hide inside normal-looking web traffic, like someone stuffing malicious code into a contact form, need a web application firewall as well. The two work together, and neither replaces keeping WordPress, themes and plugins updated.