PureBasic

SMTP over Multiple Hop SSH

Demonstrates how to send email (using TCP or TLS) tunneled through mulitple-hop SSH. The scheme looks like this:

Application => ServerSSH1 => ServerSSH2 => SmtpServer

The ConnectThroughSsh and UseSsh methods are added in Chilkat version 9.5.0.55 to accomplish this task.

PureBasic

IncludeFile "CkSsh.pb"
IncludeFile "CkEmail.pb"
IncludeFile "CkMailMan.pb"

Procedure ChilkatExample()

    success.i = 0

    ; This example requires the Chilkat API to have been previously unlocked.
    ; See Global Unlock Sample for sample code.

    ssh1.i = CkSsh::ckCreate()
    If ssh1.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Connect directly to the 1st SSH server.
    success = CkSsh::ckConnect(ssh1,"serverssh1.com",22)
    If success <> 1
        Debug CkSsh::ckLastErrorText(ssh1)
        CkSsh::ckDispose(ssh1)
        ProcedureReturn
    EndIf

    ; Authenticate using login/password:
    success = CkSsh::ckAuthenticatePw(ssh1,"ssh1Login","ssh1Password")
    If success <> 1
        Debug CkSsh::ckLastErrorText(ssh1)
        CkSsh::ckDispose(ssh1)
        ProcedureReturn
    EndIf

    ; Connect through the 1st SSH connection to reach a 2nd SSH server.
    ; Note: Any number of SSH connections may be simultaneously tunneled through a single
    ; existing SSH connection.
    ssh2.i = CkSsh::ckCreate()
    If ssh2.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkSsh::ckConnectThroughSsh(ssh2,ssh1,"serverssh2.com",22)
    If success <> 1
        Debug CkSsh::ckLastErrorText(ssh2)
        CkSsh::ckDispose(ssh1)
        CkSsh::ckDispose(ssh2)
        ProcedureReturn
    EndIf

    ; Authenticate with ssh2...
    success = CkSsh::ckAuthenticatePw(ssh2,"ssh2Login","ssh2Password")
    If success <> 1
        Debug CkSsh::ckLastErrorText(ssh2)
        CkSsh::ckDispose(ssh1)
        CkSsh::ckDispose(ssh2)
        ProcedureReturn
    EndIf

    mailman.i = CkMailMan::ckCreate()
    If mailman.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Tell the mailman object to connect to the SMTP server though the ssh2 tunnel (which itself is routed through ssh1).
    ; The connection looks like this:  Application => ServerSSH1 => ServerSSH2 => SMTPServer
    success = CkMailMan::ckUseSsh(mailman,ssh2)
    If success <> 1
        Debug CkMailMan::ckLastErrorText(mailman)
        CkSsh::ckDispose(ssh1)
        CkSsh::ckDispose(ssh2)
        CkMailMan::ckDispose(mailman)
        ProcedureReturn
    EndIf

    ; Set the SMTP server.
    CkMailMan::setCkSmtpHost(mailman, "smtp.someserver.com")

    ; Set the SMTP login/password (if required)
    CkMailMan::setCkSmtpUsername(mailman, "myUsername")
    CkMailMan::setCkSmtpPassword(mailman, "myPassword")

    ; Create a new email object
    email.i = CkEmail::ckCreate()
    If email.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkEmail::setCkSubject(email, "This is a test")
    CkEmail::setCkBody(email, "This is a test")
    CkEmail::setCkFrom(email, "Chilkat Support <support@chilkatsoft.com>")
    success = CkEmail::ckAddTo(email,"Chilkat Admin","admin@chilkatsoft.com")

    success = CkMailMan::ckSendEmail(mailman,email)
    If success <> 1
        Debug CkMailMan::ckLastErrorText(mailman)
        CkSsh::ckDispose(ssh1)
        CkSsh::ckDispose(ssh2)
        CkMailMan::ckDispose(mailman)
        CkEmail::ckDispose(email)
        ProcedureReturn
    EndIf

    ; Close the connection with the server.  This closes the tunnel through ssh2.
    success = CkMailMan::ckCloseSmtpConnection(mailman)
    If success <> 1
        Debug "Connection to SMTP server not closed cleanly."
    EndIf

    Debug "Mail Sent!"

    ; Close the connection with ssh2.  (This closes the the tunnel through ssh1.)
    ; The connection with ssh1 is still alive, and may be used for more connections.
    CkSsh::ckDisconnect(ssh2)

    CkSsh::ckDisconnect(ssh1)


    CkSsh::ckDispose(ssh1)
    CkSsh::ckDispose(ssh2)
    CkMailMan::ckDispose(mailman)
    CkEmail::ckDispose(email)


    ProcedureReturn
EndProcedure