Seven Free or Low-Cost RADIUS Servers for Your Enterprise Network - Page 3
Paid RADIUS servers
Network Policy Server (NPS) or Internet Authentication Service (IAS) is a built-in service from Windows Server. It integrates by default with Active Directory. With the GUI, the configuration becomes a breeze.
NPS and IAS are good only if the backend infrastructures rely on Microsoft technologies.
Available for Windows Server only.
I highly recommend Elektron if you want to have a reliable, non-Microsoft alternative RADIUS server.
Available for Windows and MacOS only.
The last RADIUS server that I want to highlight is Aradial. Aradial is one of the oldest RADIUS servers out there, and it is used mainly by companies that want to charge their users for the usage, e.g. ISPs. Through Aradial, users need to purchase prepaid cards or vouchers before their accounts are usable.
If you want to setup a chargeable hotspot for your users to connect to, Aradial is the one for you.
Available for Windows, Linux and Solaris.
Did I leave out any other RADIUS servers worthy of highlight? Drop me a comment below!