I always used my own IP until I got to a portal that didn't work with that. Now I use a subdomain of my site. Then one very smart captive portal "moved permanently"'d that and my browser cached it, as it should, and on the next WiFi it tried to load the old one's captive portal x_x. Not sure what the solution is for that, it would happen with neverssl or any of the alternative domains mentioned here as well. I guess you'd have to manually type a random subdomain of neverssl or so.
