windows-remote-desktop-connection-doctor_skill

Overview

This skill diagnoses Windows App (Microsoft Remote Desktop / Azure Virtual Desktop / W365) connection quality issues on macOS and guides remediation to restore optimal transport. It focuses on detecting why the client falls back to WebSocket/TCP instead of UDP Shortpath, identifying VPN/proxy interference, ISP UDP restrictions, client health-check failures, and missing server-side Shortpath. The outputs are actionable checks, log parsing hints, and recommended fixes to get UDP Shortpath restored.

How this skill works

The skill walks through a reproducible diagnostic workflow: collect Connection Info from the Windows App, capture network interface/routing and process connection evidence, inspect VPN/proxy/Tailscale state, and parse Windows App logs for STUN/TURN/Shortpath negotiation failures. It maps observed symptoms to root-cause categories (VPN/proxy, ISP, client health checks, server-side) and provides targeted verification and remediation steps.

When to use it

• VDI sessions are slow or have high RTT compared to expectations
• Windows App shows Transport Protocol = WebSocket or TCP instead of UDP
• RDP Shortpath fails to establish or no UDP connections from the client process
• Connection Info shows repeated FetchClientOptions timeouts or certificate errors
• You need to confirm whether the issue is client-side, network-side, or server-side

Best practices

• Collect Connection Info screenshot/text before making changes to preserve baseline
• Run network, process, and log checks in parallel — avoid assumptions
• Always compare a working log (UDP) with a broken log to spot missing health-check blocks
• Temporarily disable VPN/proxy when testing to isolate interference
• When changing DNS or proxy rules, document steps so you can revert if needed

Example use cases

• User reports VDI lag and Connection Info shows WebSocket — use this workflow to find if a local proxy/TUN is forcing TCP
• IT admin needs to verify whether ISP blocks UDP — run the included STUN connectivity test and routing checks
• Troubleshoot Shortpath negotiation failures by parsing Windows App logs for FetchClientOptions, STUN/TURN, and certificate errors
• Validate a fix: confirm UDP connections via lsof and observe RTT drop after applying direct/proxy exceptions
• Differentiate server-side Shortpath absence from client/network issues by checking for any STUN/TURN entries in logs