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SFS Relay Server


SFS Relay Server (STUN / TURN)​

Q1. What is SFS Relay Server?​

SFS Relay Server (Safe and Fast Streaming Relay Server) is a relay server built into the SHIELD Edge Link Outbound server, which safely delivers browser screen and data streaming between internal users and external web services in a remote browser (RBI) environment.


Q2. Why are STUN / TURN protocols necessary?​

RBI (Remote Browser Isolation) streams the remote browser screen using WebRTC technology. In this process, STUN/TURN is used for P2P connections/relays between the user PC ↔ Edge server ↔ external services.

  • STUN (Session Traversal Utilities for NAT)

    • A protocol that helps clients check their public IP and port.

    • Find the direct connection path in a NAT (Private Network ↔ Public Network) environment.

  • TURN (Traversal Using Relays around NAT)

    • If direct P2P connection is not possible, relay through the Relay server.

    • Ensuring that screen data is reliably delivered to users in the RBI environment

--> In other words, STUN attempts a direct connection / TURN acts as a relay in case of failure.


  • Internal user requests access to external website

  • Edge Link Outbound → SFS Relay Server Operation

  • Attempt direct connection if possible through the STUN server.

  • If impossible, the TURN server relays the remote browser screen to the user.


Q4. What are the benefits of using the SFS Relay Server?​

  • Stability Guarantee: Seamless access available even in firewall, NAT, and proxy environments.

  • Security Enhancement: All screens are delivered isolated through the RBI server, blocking the influx of malware.

  • Flexibility: Providing the same access experience regardless of the user environment