Captive portal basics
When a captive portal is enabled on a network, users attempting to access the network from a desktop/laptop computer or mobile device are first directed to a web page. Although captive portals can be enabled on wired networks, more typically they are used as gatekeepers on wireless networks.
Captive portal pages are displayed after a user connects to a network protected by a captive portal. The user then will try to access a URL. If the URL request comes from an unknown client, the network operating system—in this case, pfSense/FreeBSD—will recognize that users must pass through the captive portal before they have full access to the network.
The user will be redirected to a web page or splash screen. They may simply have to click on a button to indicate their agreement with the network's terms of service or an End User License Agreement (EULA), or they may have to provide login credentials. Either way, once the user is authenticated, they will have access to the network...
