CDUS Network Troubleshooting Guide
Use this guide to diagnose connection failures, verify network paths, and inspect system log outputs.
Connection Status Badges
CDUS displays a real-time status badge next to each paired device:
| Status Badge | Color | Meaning | Recovery Action |
|---|---|---|---|
| LAN | Green (#4CAF50) |
Direct peer-to-peer connection over local Wi-Fi or Ethernet. Optimal transfer speeds. | None required. |
| Relay | Orange (#EF6C00) |
Direct P2P blocked by firewall/NAT. Streaming via fallback relay. | Check router client isolation settings. |
| Offline | Red (#EF4444) |
Peer unreachable or daemon stopped. | Verify target device is powered on and running CDUS. |
Diagnosing Local Peer Discovery
CDUS uses UDP port 5353 for mDNS local discovery and TCP port 4242 for direct data transfers.
Linux Firewall (UFW)
sudo ufw allow 4242/tcp comment "CDUS Direct P2P"
sudo ufw allow 5353/udp comment "CDUS mDNS Discovery"Windows Firewall
Ensure cdus-desktop.exe has “Private Networks” permission granted in Windows Defender Firewall settings.
Wi-Fi AP Client Isolation
Many public or guest Wi-Fi networks enable Client Isolation, blocking devices on the same subnet from talking to one another.
- When client isolation is enabled, CDUS automatically switches from direct LAN to the encrypted fallback relay.
- If you prefer direct LAN speed, switch to a trusted private network or a mobile hotspot without AP isolation.
Inspecting Logs
To inspect live diagnostics from the native daemon:
# Linux
journalctl --user -u cdus-agent -f
# Or run the binary directly with debug logging
RUST_LOG=cdus=debug cdus-agent