Get-CertInfoTcp.ps1

function Get-CertInfoTcp {
    [CmdletBinding()]
    param (
        [Parameter(Position = 0, Mandatory)]
        [string] $ComputerName,

        [Parameter(Position = 1)]
        [int] $Port = 443,

        [Parameter()]
        [int] $Timeout = 3000,

        [Parameter()]
        [switch] $ReturnCertificate
    )
    try {

        $tcpClient = New-Object -TypeName System.Net.Sockets.TcpClient
        $iar = $tcpClient.BeginConnect($ComputerName,$Port,$null,$null)
        $wait = $iar.AsyncWaitHandle.WaitOne($Timeout,$false)
        if (!$wait) {
            $tcpClient.Close()
            Write-Warning 'Connection attempt timed out'
        }
        else {
            $null = $tcpClient.EndConnect($iar)

            if ($tcpClient.Connected) {
                $tcpStream = $tcpClient.GetStream()
                $sslStream = New-Object -TypeName System.Net.Security.SslStream -ArgumentList ($tcpStream, $false)
                $sslStream.AuthenticateAsClient($ComputerName)
                $certificate = New-Object -TypeName System.Security.Cryptography.X509Certificates.X509Certificate2 -ArgumentList ($sslStream.RemoteCertificate)

                if ($ReturnCertificate) {
                    Write-Output $certificate

                }
                else {
                    Write-Output ([PSCustomObject] [Ordered] @{
                        IssuerCN = $certificate.Issuer.Split(', ',[System.StringSplitOptions]::RemoveEmptyEntries)[0].Split('=')[1]
                        SubjectCN = $certificate.Subject.Split(', ',[System.StringSplitOptions]::RemoveEmptyEntries)[0].Split('=')[1]
                        ValidFrom = $certificate.NotBefore
                        ValidTo = $certificate.NotAfter
                    })
                }

                $certificate.Dispose()
                $sslStream.Close()
                $sslStream.Dispose()
                $tcpStream.Close()
                $tcpStream.Dispose()
            }
            else {
                Write-Warning "Unable to establish connection to $ComputerName on port $Port"
            }

            $tcpClient.Close()
        }
    }
    catch {
        Write-Warning $_.Exception.InnerException.Message
    }
}