(Tcl) SMTP SSH Tunneling (Port Forwarding)

Demonstrates how to setup an SSH tunnel for SMTP. This example connects to an SMTP sever via an SSH tunnel and sends an email.

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load ./chilkat.dll

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

# The mailman object is used for sending (SMTP) and receiving (POP3) email.
set mailman [new_CkMailMan]

# Connect to an SSH server and establish the SSH tunnel:

# The SSH hostname may be a hostname or an 
# IP address, such as "192.168.1.108".
# The port is typically 22 (the standard port for SSH).
set sshHostname "sftp.example.com"
set sshPort 22

set success [CkMailMan_SshOpenTunnel $mailman $sshHostname $sshPort]
if {$success != 1} then {
    puts [CkMailMan_lastErrorText $mailman]
    delete_CkMailMan $mailman
    exit
}

# Authenticate with the SSH server via a login/password
# or with a public key.
# This example demonstrates SSH password authentication.
# Note: This is not authenticating with the SMTP server, it is
# for authenticating with the SSH server, which is separate.
set success [CkMailMan_SshAuthenticatePw $mailman "sshLogin" "sshPassword"]
if {$success != 1} then {
    puts [CkMailMan_lastErrorText $mailman]
    delete_CkMailMan $mailman
    exit
}

# OK, the SSH tunnel is setup.  The mailman may
# be used exactly the same as usual, except all communications
# are now sent through the SSH tunnel.

# Set the SMTP server.
CkMailMan_put_SmtpHost $mailman "smtp.my-smtp-server.com"

# Set the SMTP login/password (if required)
CkMailMan_put_SmtpUsername $mailman "smtpLogin"
CkMailMan_put_SmtpPassword $mailman "smtpPassword"

# Create a new email object
set email [new_CkEmail]

CkEmail_put_Subject $email "This is a test"
CkEmail_put_Body $email "This is a test"
CkEmail_put_From $email "Chilkat Support <support@chilkatsoft.com>"
set success [CkEmail_AddTo $email "Chilkat Admin" "admin@chilkatsoft.com"]

# The call to SendEmail automatically connects to the SMTP
# server via the SSH tunnel (if not already connected).
# Because the SSH tunnel has been previously setup,
# this does not establish a direct connection with the SMTP
# server.  It directs the SSH server to establish the connection.

# After SendEmail completes, the connection (i.e. session) remains
# open so that subsequent SendEmail calls may use the
# same SSH tunnel.  
set success [CkMailMan_SendEmail $mailman $email]
if {$success != 1} then {
    puts [CkMailMan_lastErrorText $mailman]
    delete_CkMailMan $mailman
    delete_CkEmail $email
    exit
}

# If you're curious, have a look at LastErrorText after
# a successful send.  You'll see detailed information that 
# confirms the SSH tunneling.
puts [CkMailMan_lastErrorText $mailman]

# Note: Some SMTP servers do not actually send the email until 
# the connection is closed.  In these cases, it is necessary to
# call CloseSmtpConnection for the mail to be  sent.  
# Most SMTP servers send the email immediately, and it is 
# not required to close the connection.  

puts "Mail Sent!"

delete_CkMailMan $mailman
delete_CkEmail $email