POWERSHELL: Test https cert

TestHttpsCert.ps1

Clear-Host

$hostName = "www.microsoft.com"

$req = [System.Net.HttpWebRequest]::Create("https://$hostName")
$req.GetResponse().Dispose()
$servicePoint = $req.ServicePoint
[System.Security.Cryptography.X509Certificates.X509Certificate2]$cert = $servicePoint.Certificate

# $servicePoint | Format-List *
# $cert | Format-List *

$props = $cert | Select-Object @{Name="Address"; Expression={$servicePoint.Address}}, 
    Subject, 
    @{Name="ValidFrom"; Expression={$_.NotBefore}}, 
    @{Name="ValidTo"; Expression={$_.NotAfter}}, 
    @{Name="IsValid"; Expression={$_.Verify() -and (Get-Date) -le ([DateTime]::Parse($_.GetExpirationDateString())) }}, 
    @{Name="Encryption"; Expression={$_.SignatureAlgorithm.FriendlyName}}, 
    @{Name="DnsNames"; Expression={$_.DnsNameList.Unicode}}, 
    Issuer

$props | Out-Host

TestHttpsCertAndTls.ps1

#Requires -Version 7.0

Clear-Host

$hostName = "www.microsoft.com"
$port = 443

$tcpClient = New-Object System.Net.Sockets.TcpClient

try {
    $tcpClient.Connect($hostName, $port)
    $sslStream = New-Object System.Net.Security.SslStream($tcpClient.GetStream(), $false, ({ $true }))

    try {
        $sslStream.AuthenticateAsClient($hostName)
        $tlsVersion = $sslStream.SslProtocol
    } catch {
        Write-Error "TLS handshake failed: $_"
        $tcpClient.Close()
        return
    }

    $cert = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2($sslStream.RemoteCertificate)
    $sslStream.Close()
    $tcpClient.Close()

    # Parse SAN (DNS names) from extensions
    $sanExtension = $cert.Extensions | Where-Object { $_.Oid.FriendlyName -eq "Subject Alternative Name" }
    $dnsNames = if ($sanExtension) { $sanExtension.Format($false) } else { "N/A" }

    $props = [PSCustomObject]@{
        Address    = $hostName
        TlsVersion = $tlsVersion
        Subject    = $cert.Subject
        ValidFrom  = $cert.NotBefore
        ValidTo    = $cert.NotAfter
        IsValid    = $cert.Verify() -and (Get-Date) -le $cert.NotAfter
        Encryption = $cert.SignatureAlgorithm.FriendlyName
        DnsNames   = $dnsNames
        Issuer     = $cert.Issuer
    }

    $props | Format-List
} catch {
    Write-Error "Connection failed: $_"
}