Which security measure blocks access to websites by their URL?

A web security gateway, also known as a content filter, is specifically designed to control access to websites based on their URLs or categories. By evaluating the URLs that users attempt to access, the web security gateway can either allow or block access according to predefined policies set by an organization. This capability is essential for implementing corporate policies, maintaining compliance, and protecting users from harmful content or distractions that could negatively affect productivity or security.

Firewalls primarily act at the network level to allow or block traffic based on IP addresses, ports, and protocols rather than specifically filtering HTTP/HTTPS traffic based on URLs. Intrusion detection systems are focused on monitoring and alerting on suspicious activities or policy violations across the network, rather than actively blocking access to websites. Antivirus software helps protect systems from malware and threats, but does not specifically manage access to websites based on their URLs. Therefore, the web security gateway/content filter is the most appropriate choice for managing URL-based access.