network-connectivity-troubleshooter

# Network Connectivity Troubleshooter Use this skill when the user asks why a host, service, Connection, URL, or remote network path is unreachable or unreliable. ## Workflow 1. Identify the vantage point: local Windows shell, WSL, SSH Session, remote host, VPN, or another network segment. 2. Clarify the target as narrowly as possible: host/IP, port/protocol if known, and whether the failure is total, intermittent, slow, or one app only. 3. Separate layers before suggesting fixes: name resolution, local interface, default gateway, route, VPN/proxy, firewall, remote listener, and application protocol. 4. Prefer read-only checks first: interface state, IP address, route table, DNS answer, ping when allowed, TCP connect test, and traceroute/path trace. 5. Compare at least two vantage points when possible, such as local KKTerm terminal vs SSH Session from a nearby host. 6. Treat ICMP results carefully. A failed ping does not prove TCP is blocked, and a successful ping does not prove the service is healthy. 7. For intermittent loss or latency, ask for timing, affected destinations, wired vs wireless/VPN state, and recent network changes before recommending resets. 8. For MTU symptoms, look for large transfers hanging, VPN-only failures, TLS stalls, or SSH/SFTP freezes after login. 9. Avoid broad reset commands until targeted evidence points to local network stack corruption. ## Command Guidance - Windows reachability: `Test-NetConnection <host> -Port <port>` for TCP, `Resolve-DnsName <host>` for DNS, and `tracert <host>` for path checks. - PowerShell interface/routing: `Get-NetIPConfiguration`, `Get-NetRoute`, `Get-DnsClientServerAddress`. - POSIX/SSH vantage point: `ip addr`, `ip route`, `getent hosts <host>`, `nc -vz <host> <port>`, `tracepath <host>` or `traceroute <host>` when installed. - Keep commands read-only unless the user explicitly asks to change adapter, VPN, proxy, or route configuration. ## KKTerm Boundaries - Stored targets are Connections; live failures happen in Sessions. - Quick Connect failures may come from draft fields that are not saved yet. - URL Connections use embedded WebView2 and may be affected by OS proxy, TLS, or corporate inspection. - SSH, SFTP, RDP, VNC, URL, and local terminal checks can all provide different network vantage points.