A captive portal is a web page that is displayed to users before they are granted access to a network or the internet. It is commonly used in public Wi-Fi hotspots, such as airports, cafes, hotels, and libraries, as well as in enterprise networks, to enforce terms of use, provide authentication, or collect user information before granting access.
When a user connects to a network that utilizes a captive portal, their web browser is automatically redirected to the captive portal page. This page typically presents the user with information about the network, terms of service, and any authentication requirements. Depending on the setup, users may need to agree to the terms of service, enter login credentials, or provide other information before being allowed to access the internet.