Dynamic Clients IP Best practice?

I unfortunately have a large amount of hotspots that are behind dynamic ip's. We have tried to get as many of them onto statics as possible but are having issues with that. After having read through a few dozen different threads and readmes does freeradius have something that has been put into place to address this?( I assume the answer is no or I glazed over while reading and missed the answer) . If there is no built in feature is there a best practice for this? Reverse DNS and / or VPN tunnels are the 2 solutions I can think of that would secure the nas check. Is there something else I am missing I can read up on and look into? Thanks Brent