(Tcl) 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.

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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.

set ssh1 [new_CkSsh]

# Connect directly to the 1st SSH server.
set success [CkSsh_Connect $ssh1 "serverssh1.com" 22]
if {$success != 1} then {
    puts [CkSsh_lastErrorText $ssh1]
    delete_CkSsh $ssh1
    exit
}

# Authenticate using login/password:
set success [CkSsh_AuthenticatePw $ssh1 "ssh1Login" "ssh1Password"]
if {$success != 1} then {
    puts [CkSsh_lastErrorText $ssh1]
    delete_CkSsh $ssh1
    exit
}

# 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.
set ssh2 [new_CkSsh]

set success [CkSsh_ConnectThroughSsh $ssh2 $ssh1 "serverssh2.com" 22]
if {$success != 1} then {
    puts [CkSsh_lastErrorText $ssh2]
    delete_CkSsh $ssh1
    delete_CkSsh $ssh2
    exit
}

# Authenticate with ssh2...
set success [CkSsh_AuthenticatePw $ssh2 "ssh2Login" "ssh2Password"]
if {$success != 1} then {
    puts [CkSsh_lastErrorText $ssh2]
    delete_CkSsh $ssh1
    delete_CkSsh $ssh2
    exit
}

set mailman [new_CkMailMan]

# 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
set success [CkMailMan_UseSsh $mailman $ssh2]
if {$success != 1} then {
    puts [CkMailMan_lastErrorText $mailman]
    delete_CkSsh $ssh1
    delete_CkSsh $ssh2
    delete_CkMailMan $mailman
    exit
}

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

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

# 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"]

set success [CkMailMan_SendEmail $mailman $email]
if {$success != 1} then {
    puts [CkMailMan_lastErrorText $mailman]
    delete_CkSsh $ssh1
    delete_CkSsh $ssh2
    delete_CkMailMan $mailman
    delete_CkEmail $email
    exit
}

# Close the connection with the server.  This closes the tunnel through ssh2.
set success [CkMailMan_CloseSmtpConnection $mailman]
if {$success != 1} then {
    puts "Connection to SMTP server not closed cleanly."
}

puts "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_Disconnect $ssh2

CkSsh_Disconnect $ssh1

delete_CkSsh $ssh1
delete_CkSsh $ssh2
delete_CkMailMan $mailman
delete_CkEmail $email