Xojo Plugin

Get the SMTP or POP3 Server's TLS Certificate

Demonstrates the Chilkat MailMan.GetServerCert method, which gets the digital certificate presented by the SMTP or POP3 server for the current SSL/TLS connection and stores it in a Cert object. Pass true for the SMTP server's certificate or false for the POP3 server's. This example connects to the SMTP server and prints the certificate's subject and issuer.

Background: During a TLS handshake the server presents a certificate proving its identity, and the client validates it against trusted authorities. Retrieving that certificate lets you inspect it yourself — checking the subject, issuer, or expiration for auditing, logging, or certificate-pinning style checks. It must be called while a TLS connection is established, since the certificate belongs to that specific session.

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Xojo Plugin

Dim success As Boolean
success = False

//  Demonstrates the MailMan.GetServerCert method, which gets the digital certificate
//  presented by the SMTP or POP3 server for the current SSL/TLS connection.  Pass 1 for
//  the SMTP server's certificate, or 0 for the POP3 server's certificate.

Dim mailman As New Chilkat.MailMan

//  Configure the SMTP server connection.
mailman.SmtpHost = "smtp.example.com"
mailman.SmtpPort = 465
mailman.SmtpSsl = True
mailman.SmtpUsername = "user@example.com"
mailman.SmtpPassword = "myPassword"

//  Establish the TLS connection.
success = mailman.SmtpConnect()
If (success = False) Then
    System.DebugLog(mailman.LastErrorText)
    Return
End If

//  Get the certificate the SMTP server presented (useSmtp = cktrue).
Dim cert As New Chilkat.Cert
success = mailman.GetServerCert(True,cert)
If (success = False) Then
    System.DebugLog(mailman.LastErrorText)
    Return
End If

System.DebugLog("Server certificate subject (CN): " + cert.SubjectCN)
System.DebugLog("Issued by: " + cert.IssuerCN)

success = mailman.CloseSmtpConnection()
If (success = False) Then
    System.DebugLog(mailman.LastErrorText)
    Return
End If