PowerShell: Test-NetConnection and TNC
Ping succeeds but HTTPS fails. Test the exact TCP port, inspect route diagnostics, and use the built-in tnc alias. Work through it yourself in the live host terminal below.
Symptom
Ping succeeds but HTTPS fails. Test the exact TCP port, inspect route diagnostics, and use the built-in tnc alias.
Your mission
Inspect, recover, then verify
Format
Windows PowerShell
Investigate before you configure.
Use the CLI evidence to isolate the fault, make the smallest safe correction, then verify the network state changed.
Observe the symptom and link state.
Diagnose by comparing the protocol evidence.
Verify the expected device state and confirm the original symptom is resolved.
Console access: PowerShell
This workspace stacks for portrait phones. Rotate to landscape for the full split-screen console.
Need a hint?
Reveal the root cause when you're ready.
Try the investigation first, then use this as your escape hatch, not a dead end.
Lab debrief
Turn the session into a repeatable troubleshooting pattern.
Use this reference after your attempt: first explain the symptom, then verify the evidence, then confirm the repair.
The problem
`app.lab.example` resolves and responds to ICMP, but the browser cannot establish HTTPS on TCP 443.
What you'll practice
- Run Test-NetConnection for ICMP reachability
- Test a specific TCP port
- Interpret TcpTestSucceeded
- Use Get-Alias to verify tnc
- Use tnc as the short alias
The topology
A Windows client reaches an internal application through one gateway. The server responds to ping but initially has no TCP 443 listener.
Commands to run yourself
The real diagnostic commands for this lab, copy-paste ready. Run these in the same order to reproduce the investigation on your own session.
Test-NetConnection -ComputerName app.lab.exampleTest-NetConnection -ComputerName app.lab.example -Port 443Topology diagram
Fact-checked references
The commands and behaviour in this lab were checked against these primary references.
Frequently asked
Is tnc a different tool?
No. It is a built-in alias for Test-NetConnection in Windows PowerShell. The output and parameters belong to the same cmdlet.
Why can ping succeed while port 443 fails?
ICMP reachability and a TCP listener are separate. A firewall or missing service can block the port while the host still answers ping.
Ready to run this lab yourself?
No setup, no image sourcing. Book a session or ask for a live demo.