Antonello, There is no better solution for all possible cases. The solutions have differences explained in the readme files for example RTP proxy can take more load per server, Media Proxy can distribute load on multiple boxes based on DNS SRV records and STUN can help your Stun enabled clients to traverse the NAT in majority of cases but not all. So a combination between STUN plus one of the relay solutions will cover all cases. Configuring per session when to use Stun or a media relay is quite a daunting task given the number of possible call flow scenarios so if you wish that your calls always work regardless of UA type or call flow you will enable a media relay because Stun is not reliable 100%. Adrian Terrible question: Is mediaproxy better than rtp or STUN server for NAT problem ??? Radius Authentication work fine with Mediaproxy, STUN and RTP ? In Mediaproxy Server, radius auth supported only in non-free version (7.000,00 euro) ! My work is: Private Network for more than 1000 users Public SER SERVER Public Radius+MySQL Public Patton MediaGW Please, answer ! Thanks Antonello