How to organize a single point of authentication for wifi users via SMS?

Question

linux

Hello,
some time ago I implemented SMS authorization for a hotel client to access open Wifi. The system is as simple as a bellow and as trouble-free as a Kalashnikov assault rifle: the client connects to the hotspot, when he tries to open any page, he is forwarded to the authorization web face, where he enters his mobile phone. After that, he receives an SMS with a pin, he drives it in and uses it.
As you may have guessed, all the magic here is happening on the gateway, and more specifically in the iptables rules, and even more specifically in the poppies freely walking around the LAN. Now I have received three more similar orders and I am seriously thinking about a single point of authentication without replacing or additional installation of hardware for clients. Do you have any ideas how this can be implemented? If I don’t confuse, did Beeline do something similar in cafes or did they change routers to their own?

Answer 1

By default, all users on the gateway are redirected to the external server. In the event that the external server on the radius gives the go-ahead "access-accept", the gateway removes the iptables rule with a redirect and gives access to the Internet.
Google towards "Linux ISG"

Answer 2

mikrotik hotspot + external radius + external site for registration