How to Test UDP Ports on Windows 10 Using Netcat and PowerShell

Method 1: Netcat (nc)

Install Netcat via Cygwin or Git for Windows.

Download Cygwin from https://cygwin.com/ and select the netcat package during setup.

Download Git for Windows from https://git-scm.com/download/win; it includes nc.exe.

Test a UDP port: echo "hello" | nc -u serverB 123 The -u flag selects UDP.

Method 2: PowerShell script

Create a script test-udp.ps1 with the following content:

$remoteHost = "serverB"
$remotePort = 123
$data = "Hello, UDP!"

# Create a UDP client
$client = New-Object System.Net.Sockets.UdpClient
# Send data
$client.Send([Text.Encoding]::ASCII.GetBytes($data), $data.Length, $remoteHost, $remotePort)
# Close client
$client.Close()

Run the script from an elevated PowerShell prompt:

powershell -ExecutionPolicy Bypass -File test-udp.ps1

Method 3: Using ping for basic reachability

Windows 10 does not include a native UDP testing tool. You can use ping to verify that the host is reachable, which does not confirm UDP port availability:

ping -n 1 serverB

Important notes

UDP is connectionless; sending a packet may not produce a response.

To verify UDP port reachability, send a packet and observe whether any error messages are generated.