Test-TlsProtocol.ps1

function Test-TlsProtocol {
<#
	.SYNOPSIS
		A quick helper function to test supported TLS protocols
	
	.DESCRIPTION
		A quick helper function to test supported TLS protocols
	
	.PARAMETER ComputerName
		The hosts to check.
	
	.PARAMETER Port
		The Port to test against.
		Defaults to 443
	
	.EXAMPLE
		PS C:\> Test-TlsProtocol -ComputerName 'contoso.com'
	
		Tests contoso.com's supported TLS protocols (at least as far as the service listening on Port 443 is concerned).
#>
	[CmdletBinding()]
	param (
		[Parameter(Mandatory = $true, ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true)]
		[ValidateNotNullOrEmpty()]
		[string[]]
		$ComputerName,
		
		[UInt16]
		$Port = 443
	)
	begin {
		$tlsProtocols = [enum]::GetNames([System.Security.Authentication.SslProtocols]) | Where-Object { $_ -ne 'None' }
		$certificateCallback = [System.Net.Security.RemoteCertificateValidationCallback]{ $true }
	}
	process {
		:main foreach ($computer in $ComputerName) {
			$results = @{
				Host		  = $computer
				Port		  = $Port
				KeyExhange    = $null
				HashAlgorithm = $null
				Error		  = @{ }
			}
			
			foreach ($tlsProtocol in $tlsProtocols) {
				$tcpClient = [Net.Sockets.TcpClient]::new()
				try { $tcpClient.Connect($computer, $Port) }
				catch {
					$tcpClient.Dispose()
					Write-Warning "[$computer] Error connecting: $($_.Exception.GetBaseException().Message)"
					Write-Error $_
					if ($_.Exception.InnerException.SocketErrorCode -eq 'HostNotFound') { continue main }
					continue
				}
				
				$sslStream = [Net.Security.SslStream]::new(
					$tcpClient.GetStream(),
					$true,
					$certificateCallback
				)
				
				try {
					$sslStream.AuthenticateAsClient($results.Host, $null, $tlsProtocol, $false)
					$results.KeyExhange = $sslStream.KeyExchangeAlgorithm
					$results.HashAlgorithm = $sslStream.HashAlgorithm
					$results.$tlsProtocol = $true
				}
				catch {
					$results.$tlsProtocol = $false
					$results.Error.$tlsProtocol = $_
				}
				finally {
					$tcpClient.Dispose()
					$sslStream.Dispose()
				}
			}
			
			[pscustomobject]$results
		}
	}
}