what is it called when ater logging into a wifi router it redirects a url to a log-in page...

i am wanting to set up a public wifi-router (with no internet access connected) that after logging in redirects any page to a main page

some time ago i tried configuring a telstra 3G21WB to do this using the DMZ zone, built in DNS server and usb port to hold the pages but i was unsuccessful.

i;ve still got that router plus another cable router with wifi, a CG814WG which i would also like to use in conjunction with a lappy ive got running a zoneminder server... so im probably looking at two different methods, i think...

thanks for any help, will be much appreciated..

that's a seriousy cool name for something, ta