State of knowledge

January 2024

Interoperability is only ensured with estos products such as ProCall Enterprise. No other applications have been certified for ProCall mobility services.


estos operates a STUN/TURN service for its products in the OVH cloud ( in Europe on the basis of coturn (

Other services provided via ProCall mobility services are proprietary and specific to estos products, such as ensuring push messages for smartphone apps or the VPN-less operation supported from ProCall 8 Enterprise as a proxy between the ProCall clients and the ProCall Enterprise UCServer.

Network topology

Network addresses and port ranges are documented in under UCConnect/UCTurn. These are updated here when the configuration is changed.

STUN/TURN performance features

STUN specifications

  • RFC 3489 - "classic" STUN
  • RFC 5389 - base "new" STUN specs
  • RFC 5769 - test vectors for STUN protocol testing
  • RFC 5780 - NAT behavior discovery support
  • RFC 7443 - ALPN support for STUN & TURN
  • RFC 7635 - oAuth third-party TURN/STUN authorization

TURN specifications

ICE and relevant specifications

Client-to-TURN protocol support

Relay Protocols

Template for tenders

If you are interested in a template for tenders, please contact us at

ProCall Enterprise service specifications