Visual Basic 6.0

Verify Connectivity to the SMTP Server

Demonstrates the Chilkat MailMan.VerifySmtpConnection method, which tests whether a TCP/IP connection can be established with the configured SMTP server. It verifies connectivity only — it does not authenticate. This example configures the SMTP host and checks whether it can be reached.

Background: When a send fails, it helps to know where it broke. VerifySmtpConnection isolates the first hop — can the client even reach the server on the configured host and port, and complete the TLS handshake? A failure here points at networking, firewall, DNS, port, or certificate issues rather than credentials. Once connectivity is confirmed, VerifySmtpLogin tests the authentication step.

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Visual Basic 6.0

'  Demonstrates the MailMan.VerifySmtpConnection method, which tests whether a TCP/IP
'  connection can be established with the configured SMTP server.  It verifies connectivity
'  only (it does not authenticate).

Dim mailman As New ChilkatMailMan

'  Configure the SMTP server connection.
mailman.SmtpHost = "smtp.example.com"
mailman.SmtpPort = 465
mailman.SmtpSsl = 1

'  Test connectivity to the SMTP server.
Dim connected As Long
connected = mailman.VerifySmtpConnection()

If (connected = 1) Then
    Debug.Print "Successfully connected to the SMTP server."
Else
    Debug.Print "Could not connect to the SMTP server."
End If