VB.NET

Enumerate Server-Advertised Acceptable Client CAs

Demonstrates Socket.GetSslAcceptableClientCaDn, which returns a certificate-authority distinguished name advertised by a TLS server when it requests a client certificate.

Background. Valid indexes range from 0 through NumSslAcceptableClientCAs minus one. A client can use these names to select an appropriate client certificate.

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VB.NET

Dim success As Boolean = False

Dim socket As New Chilkat.Socket

'  Connect to the server using TLS.
Dim bTls As Boolean = True
Dim maxWaitMs As Integer = 5000
success = socket.Connect("example.com",5000,bTls,maxWaitMs)
If (success = False) Then
    Debug.WriteLine(socket.LastErrorText)
    Exit Sub
End If


'  After connecting to a server that requests a client certificate, enumerate the certificate-
'  authority distinguished names the server advertised as acceptable.
Dim numCAs As Integer = socket.NumSslAcceptableClientCAs
Dim i As Integer
For i = 0 To numCAs - 1
    Dim caDn As String = socket.GetSslAcceptableClientCaDn(i)
    If (socket.LastMethodSuccess = False) Then
        Debug.WriteLine(socket.LastErrorText)
        Exit Sub
    End If

    Debug.WriteLine(caDn)
Next