Powershell – Test TCP ports on remote servers

Standard

From time to time it is necessary to check if specific TCP ports are open on remote servers. If you have many servers to check it can be a hassle to use telnet or other tools and check each server one by one. It is also often useful in other scripts to test if a remote server/port is alive before running code on them. To accomplish this I have written this little function.

function Test-PortAlive {
	#############################################################################################
	##Function:			Test-PortAlive
	##
	##Description:		Tests connection on a given server on a given port.
	##
	##Created by:		Noam Wajnman
	##Creation Date:	April 02, 2014	
	##############################################################################################
	[CmdletBinding()]
	[OutputType([System.boolean])]
	param(
		[Parameter(ValueFromPipeline=$true)][System.String[]]$server,
		[int]$port
	)
	$socket = new-object Net.Sockets.TcpClient
	$connect = $socket.BeginConnect($server, $port, $null, $null)
	$NoTimeOut = $connect.AsyncWaitHandle.WaitOne(500, $false)
	if ($NoTimeOut) {
		$socket.EndConnect($connect) | Out-Null
		return $true				
	}
	else {
		return $false
	}
}

The function takes two parameters $server and $port. $server is the name of the remote server to test and $port is the number of the TCP port to check the status of. The $server parameter can even be passed via the pipeline making it very easy to run. The function returns either $true or $false depending on whether the port is open or not. To avoid long wait times due to closed ports I have included a relatively short timeout value of 500 ms before the result is determined.
I have included a few examples below of how to call the function.
1. Normal

 
Test-PortAlive -port 135 "some_server" 

Here I just run the function as normal and pass both params. I chose port 135 in this example but it could be any port.
2. Pipeline

 
$Array_of_Server_Names | Test-PortAlive -port 135

In this example I am using an array to pass the server names to the function via the pipeline. I again chose port 135 in this example.

That’s it. I hope you find this function useful. Enjoy!!

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2 thoughts on “Powershell – Test TCP ports on remote servers

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