Remember: Green = Direct UDP (Good). Yellow = Relay TCP (Bad).
Open CMD as Admin and type: ping <friends_radmin_ip> -n 50 If you get 0% loss and <50ms latency, the relay is dead. You have won. radmin vpn relay tcp fix work
| Step | Action | Success Indicator | | :--- | :--- | :--- | | 1 | Disable IPv6 on Radmin adapter | No more "IPv6 handshake failures" | | 2 | Add UDP 33640-33642 to Firewall | Windows stops blocking the handshake | | 3 | Port forward UDP 33640-33642 on router | Router stops blocking inbound UDP | | 4 | Disable antivirus "Web Shield" temporarily | Real-time HTTPS scanning kills VPNs | | 5 | Both users change DNS to Cloudflare (1.1.1.1) | Prevents ISP hijacking of VPN queries | Remember: Green = Direct UDP (Good)
A: Your router’s NAT table is full. Reboot your router weekly. Also, disable "Energy Efficient Ethernet" in your network card properties. You have won
A: No. The software requires TCP as a fallback. That is the "Relay." You cannot disable it; you can only make it unnecessary by fixing UDP. Conclusion: Stop Using the Relay The Radmin VPN Relay TCP fix is not one click—it is a diagnosis. 80% of users solve it with the Firewall + Port Forwarding combination (Part 2 & 3). 15% need to disable IPv6. The remaining 5% (CGNAT victims) need a secondary VPN like ZeroTier.
Here is the hard truth: When it cannot establish that direct line, it falls back to a "Relay" server (TCP – Transmission Control Protocol). This relay is a bottleneck. It introduces high latency and packet loss, making gaming or remote work impossible.