Firewall

A firewall controls incoming and outgoing traffic ✕ Traffic is the amount of data your website transfers, determined by visitor numbers and page size. Some hosting plans cap monthly traffic. More in the glossary → according to set rules and decides which connections are allowed and which are blocked. This stops outside attackers from reaching open services and prevents malware ✕ Malware (from "malicious software") is the umbrella term for any harmful software — viruses, trojans, ransomware, spyware — that damages, spies on, or hijacks devices. More in the glossary → from quietly "phoning home." There are software firewalls (in the operating system or security suites) and hardware firewalls (e.g., in your router). It doesn't replace antivirus ✕ An antivirus is a program that detects, blocks and removes malicious software. Modern ones combine known signatures with behavior analysis. More in the glossary → but complements it: it governs network access while antivirus detects malicious files. Many suites combine both — see the best antivirus comparison.