NoCatSplash is a Open Public Network Gateway Daemon.  It performs as a
[captive/open/active] portal.  When run on a gateway/router on a network,
all web requests are redirected until the client either logs in or clicks
"I Accept" to an AUP. The gateway daemon then changes the firewall rules
on the gateway to pass traffic for that client (based on IP address and
MAC address).

Bruce
bms@FreeBSD.org