Test a TCP port across servers
Documentation: Microsoft Learn
The loop walks $Computers and calls Test-NetConnection against each with the port held in $Port, capturing the result object.
The script
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$Computers = "SRV01"
$Port = 443
foreach($Computer in $Computers){ $r = Test-NetConnection $Computer -Port $Port -WarningAction SilentlyContinue; [pscustomobject]@{Computer= $Computer;Port= $Port;Reachable= $r.TcpTestSucceeded} }- Stage 1$Computers
Positional values or no named parameters
How it works
The loop walks $Computers and calls Test-NetConnection against each with the port held in $Port, capturing the result object. A [pscustomobject] then records the host name, the port, and TcpTestSucceeded, which is the boolean saying whether the handshake actually completed.
Adapting it
Wrap the loop body in Start-ThreadJob or move to a parallel ForEach-Object, since every failing host costs a full TCP timeout and a serial run across fifty targets stretches into minutes.
If the result is unexpected
A TCP test fails while a service works from another machine.
Firewall policy, routing and listening addresses can differ by source and destination.
- Run the same host and port check from the affected source and inspect the target listener.
Validate the result
The intended source can establish TCP to the expected address and port.
Keep the check reliable
Record source host, resolved address and port; a TCP success does not validate the application protocol.
