(VB.NET) FTP Connect, Examine Server Certificate, and then Authenticate

Demonstrates how to connect to an FTP server, examine the server's SSL/TLS certificate, and then, if it meets the application's security requirements, proceed to authenticate.

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' This example assumes Chilkat Ftp2 to have been previously unlocked.
' See Unlock Ftp2 for sample code.

Dim ftp As New Chilkat.Ftp2

ftp.Hostname = "www.authtls-ftps-server.com"
ftp.Username = "FTP_LOGIN"
ftp.Password = "FTP_PASSWORD"
ftp.AuthTls = True
ftp.Port = 21

' Connect to the FTP server using explicit TLS (AUTH TLS).
Dim success As Boolean = ftp.ConnectOnly()
If (success <> True) Then
    Debug.WriteLine(ftp.LastErrorText)
    Exit Sub
End If


' Get the FTP server's certificate.
Dim serverCert As Chilkat.Cert = ftp.GetSslServerCert()
If (ftp.LastMethodSuccess <> True) Then
    Debug.WriteLine(ftp.LastErrorText)
    Exit Sub
End If


' Now that we have the certificate, we can check it in any way we desire.
' (See the online reference documentation for the certificate object's methods
' and properties)...

' Assuming the certificate is OK, proceed to authenticate with the FTP server.
success = ftp.LoginAfterConnectOnly()
If (success <> True) Then
    Debug.WriteLine(ftp.LastErrorText)
    Exit Sub
End If


' 
' Proceed with uploading/download files, etc...
' 


ftp.Disconnect()
Debug.WriteLine("Success.")