💁 GTR FAQ

Remote Support: Transition from TeamViewer to RustDesk

7 min read

tl;dr

Overview

We are transitioning our remote support infrastructure from TeamViewer to RustDesk to provide better security, transparency, and cost efficiency. This document guides both end-users and IT administrators through the transition process and technical requirements for cloud-hosted remote support sessions. The transition to RustDesk will be finished until the end of 2025.

Key Advantages of RustDesk:

  • Open-source codebase with transparent security model and public audit possibilities
  • End-to-end encryption (RSA 4096 + AES 256-bit)
  • Improved performance and lower latency
  • Industry-standard security protocols

For End Users

What’s Changing?

TeamViewer is being replaced with RustDesk for remote support sessions. The user experience will be familiar, but with improved speed and security.

System Requirements

RustDesk is compatible with a wide range of platforms:

Operating SystemMinimum Version
WindowsWindows 7 and later
macOSmacOS 10.12 (Sierra) and later
LinuxUbuntu 16+, CentOS, Fedora, Debian derivatives, Arch, openSUSE, NixOS
OtherAndroid, iOS (receive-only), Web browser access

Hardware Requirements:

  • Modest CPU and RAM requirements; runs on older systems
  • Minimum 1 Mbps internet connection recommended

Getting Started

  1. Download: Visit rustdesk.com or rustdesk on github and download the client for your operating system
  2. Install: Depending on the Operating Systems, an Installation may be required. Follow standard installation process, by executing the downloaded file. On Windows RustDesk can be run without installation
  3. Connect: Pass the automatically generated ID and one time password to the GTR engineer to establish the connection.
  4. Session: Support engineer/technician controls your desktop with your permission

Technical Comparison: TeamViewer vs RustDesk

FeatureTeamViewerRustDesk
Code TransparencyProprietary (closed-source)Open Source (GPLv3)
EncryptionAES-256RSA 4096 + AES-256 (end-to-end)
Server HostingCloud-onlyCloud-hosted
PerformanceGoodExcellent (optimized P2P architecture)
Connection SetupSimpleSimple
Port UsageDynamicFixed (see admin section)
AuditabilityLimited (proprietary)Full (open-source)

What to Expect During a Support Session

  • You will see the RustDesk client request your permission before any connection begins
  • Your desktop will be visible to the support technician while the session is active
  • Audio and file transfer may be available depending on session configuration
  • You can terminate the connection at any time
  • All sessions are encrypted end-to-end

For IT Administrators

Network Requirements - Client-Side Outbound Connections

RustDesk requires specific outbound network access to function properly. Configure your firewall to allow the following outbound connections from client machines:

Required Outbound Ports

ProtocolPortDirectionPurposeNotes
TCP21115OutboundControl & command connectionPrimary connection
TCP21116OutboundRelay fallbackUsed if UDP blocked
UDP21116OutboundRelay connectionPreferred for better performance

Important Notes:

  • Port 21115 (TCP) handles command and control signals
  • Port 21116 should be enabled for both TCP and UDP for optimal performance
  • UDP connection is attempted first; TCP is used as fallback if UDP is blocked
  • All connections use TLS 1.2 or higher encryption

Windows Firewall (Outbound Rule)

Rule Name: RustDesk Remote Support
Direction: Outbound
Protocol: TCP/UDP
Remote Port: 21115, 21116
Remote Address: Any
Action: Allow

Linux (UFW)

sudo ufw allow out 21115/tcp
sudo ufw allow out 21116/tcp
sudo ufw allow out 21116/udp

Linux (firewalld)

sudo firewall-cmd --permanent --add-port=21115/tcp --zone=public
sudo firewall-cmd --permanent --add-port=21116/tcp --zone=public
sudo firewall-cmd --permanent --add-port=21116/udp --zone=public
sudo firewall-cmd --reload

pfSense / Enterprise Firewall

Create outbound rules allowing traffic to any destination on ports 21115 and 21116 (both TCP and UDP). Consider creating a traffic alias for easier management:

Alias: RustDesk_Ports = 21115, 21116

Firewall Rule:
- Direction: Outbound
- Protocol: TCP/UDP
- Destination Port: RustDesk_Ports
- Action: Pass
- Log: Optional (for audit trails)

VPN & Proxy Configuration

VPN Passthrough:

  • RustDesk works transparently through most VPN connections without special configuration
  • Ensure VPN network policies don’t block ports 21115/21116
  • For split-tunnel VPNs, ensure RustDesk traffic routes through the VPN tunnel

Proxy Support:

  • RustDesk supports HTTP and HTTPS proxy with authentication
  • Configure proxy settings in the RustDesk client:
    • Open RustDesk → Settings → Network
    • Enter proxy server address, port, username, and password (if required)
  • Proxy authentication supports basic credentials
  • If your firewall performs SSL inspection, consider adding exceptions for RustDesk connections to avoid performance issues

Firewall SSL Inspection:

  • If your firewall performs SSL/TLS inspection, whitelist RustDesk servers or disable inspection for RustDesk traffic
  • SSL inspection can cause connection delays or failures

Bandwidth & Performance Considerations

Connection Overhead:

  • Baseline (idle): 50-100 KB/s
  • Active session (screen sharing): 200 KB/s - 2 MB/s (depends on resolution and activity)
  • Audio only: 20-50 KB/s
  • File transfer: Varies based on file size and network speed

Typical Bandwidth Usage:

  • Standard screen (1920x1080): 500 KB/s - 1.5 MB/s for typical desktop activity
  • High-resolution (2560x1440): 1 MB/s - 2.5 MB/s
  • Low-resolution/minimal updates: 100-300 KB/s

Recommended Minimum Connection Speed:

  • 1 Mbps for basic remote support
  • 5 Mbps for comfortable interactive sessions
  • 10+ Mbps for multiple concurrent sessions or high-resolution screens

Latency:

  • Direct connections: <50ms typical
  • Relay connections: <200ms typical
  • Connection type depends on network NAT configuration and firewall settings

IT Administrator Deployment Checklist

  • Review and approve firewall port requirements (21115 TCP, 21116 TCP/UDP outbound)
  • Configure firewall rules in your environment
  • Test RustDesk connectivity from sample client systems behind firewall
  • Verify proxy/SSL inspection exceptions are in place if applicable
  • Document the connection process for your help desk team
  • Test file transfer functionality if required for support workflows
  • Establish audit logging requirements and procedures
  • Create troubleshooting documentation for help desk

Bandwidth Planning for Administrators

Capacity Calculations:

  • For concurrent sessions: Multiply typical bandwidth per session by max concurrent support sessions
  • Example: 3 concurrent sessions × 1 MB/s = 3 MB/s minimum pipe capacity
  • Add 20-30% overhead for protocol negotiation and network variations

Network Policy Considerations:

  • Configure QoS (Quality of Service) rules if RustDesk conflicts with business-critical traffic
  • RustDesk can be prioritized as lower priority than production traffic
  • Monitor bandwidth usage to identify any anomalies

Troubleshooting

Connection Failures

Problem: “Cannot connect to RustDesk server”

Troubleshooting steps:

  1. Verify TCP 21115 and UDP/TCP 21116 are open outbound in firewall
  2. Test connectivity with: telnet rustdesk-servers.com 21115 (or use PowerShell)
  3. If behind proxy: Verify proxy settings in RustDesk client (Settings → Network)
  4. Temporarily disable VPN to test direct connectivity
  5. Check if SSL inspection is blocking the connection; try adding exception
  6. Contact support if issue persists

Problem: “Connection times out after initial connect”

Troubleshooting steps:

  1. May indicate relay server issue; ensure both TCP and UDP rules are open
  2. Verify UDP 21116 is specifically allowed in firewall
  3. Test latency: ping rustdesk-server-dns.com
  4. If latency is very high (>500ms), connection may be routed through relay
  5. Try switching between direct/relay modes if available in client settings

Performance Issues

Slow screen updates:

  • Check available bandwidth using speedtest or similar tool
  • Reduce screen resolution or quality settings in RustDesk client
  • Verify no competing network usage on that connection
  • Switch from relay to direct connection if possible

High latency:

  • Latency >100ms may indicate relay connection instead of direct
  • Check network path with tracert/traceroute to see route to server
  • If using VPN, verify VPN server location is optimal

Audio/Video issues:

  • Try disabling audio if video connection is priority
  • Reduce video resolution in client settings
  • Verify network bandwidth is sufficient for session type

Common Error Messages

ErrorCauseSolution
”Failed to authenticate”Credentials incorrect or session expiredVerify authentication credentials; restart client
”Network unreachable”Firewall blocking portsCheck firewall rules; verify ports 21115/21116 are open
”Connection refused”Server unreachableVerify server address in settings; check DNS resolution
”Relay server error”Can’t reach relayBoth TCP and UDP on 21116 must be open

Support & Resources

For End-Users:

For IT Administrators:

Internal Support:

FAQ

Q: Is RustDesk safe? A: Yes. RustDesk uses end-to-end encryption with RSA 4096-bit keys and AES-256 encryption. The open-source code has been publicly audited, and the support servers are managed professionally.

Q: Will my files be visible during a support session? A: The technician will have full screen access during the session. File transfer is a separate function that requires explicit permission. All data remains encrypted.

Q: What happens to my data? A: All data is encrypted end-to-end. RustDesk servers cannot decrypt your session data. For cloud-hosted deployments, data in transit is protected but not stored on servers.

Q: Do I need to allow TeamViewer anymore? A: No, after the transition period TeamViewer access can be disabled.

Q: Why is RustDesk better than TeamViewer? A: RustDesk offers open-source transparency, better performance, lower cost, and end-to-end encryption. The code can be audited publicly, providing better security assurance.

Q: What if my firewall is very restrictive? A: RustDesk can work through proxies and most firewalls using ports 21115 and 21116. If all ports are blocked, contact IT to discuss exceptions. RustDesk can also work through VPNs.

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