My scenario is as follow: I use more then one strong authentication system, which is OTP (One Time Password) based and has a RADIUS interface. I use the same users repository for the various authentication systems and wish to differ between the authentication systems, using Free RADIUS .Net. I wouldn't like to use realms, as I would like users to use ordinary username and not make them use a realm. I think that the way to do it, is to create sort of loop, which will run through the various RADIUS interfaces of the OTP systems and seek for a given username. If it fails on one system, continue to the next one, and if not found in any of them, send reject access response. Best, Ronen.