(Tcl) Verify FTP SSL Server Certificate

This example demonstrates how to verify the FTP server's certificate and authenticity. The intent is to verify the authenticity of the server before passing a login/password to it.

Chilkat Tcl Extension Downloads Chilkat Tcl Extension Downloads

load ./chilkat.dll

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

set ftp [new_CkFtp2]

CkFtp2_put_Hostname $ftp "ftp.myftpserver.com"
CkFtp2_put_Username $ftp "myUsername"
CkFtp2_put_Password $ftp "myPassword"

# Establish an AUTH SSL secure channel after connection
# on the standard FTP port 21.
CkFtp2_put_AuthSsl $ftp 1

# The Ssl property is for establishing an implicit SSL connection
# on port 990.  Do not set it.
CkFtp2_put_Ssl $ftp 0

# Indicate that the FTP server must have a verifiable SSL certificate.
# Do not accept self-signed certs or certificates that are
# expired, revoked, or cannot be verified to a root authority:
CkFtp2_put_RequireSslCertVerify $ftp 1

# You may also set a requirement.  In this example,
# the certificate's Common Name (CN) must match the
# required string exactly:
CkFtp2_SetSslCertRequirement $ftp "subjectcn" "Chilkat Software, Inc."

# Connect and login to the FTP server.
set success [CkFtp2_Connect $ftp]
if {$success != 1} then {
    puts [CkFtp2_lastErrorText $ftp]
    delete_CkFtp2 $ftp
    exit
} else {
    # LastErrorText contains information even when
    # successful. This allows you to visually verify
    # that the secure connection actually occurred.
    puts [CkFtp2_lastErrorText $ftp]
}

# After logging on, you may examine the FTP server's cert:
# cert is a CkCert

set cert [CkFtp2_GetSslServerCert $ftp]
if {[CkFtp2_get_LastMethodSuccess $ftp] != 1} then {
    puts "No server certificate!"
} else {
    # Display the distinguished name of the SSL cert.
    puts [CkCert_subjectDN $cert]
}

puts "Secure FTP Channel Established!"

# Do whatever you're doing to do ...
# upload files, download files, etc...

set success [CkFtp2_Disconnect $ftp]

delete_CkFtp2 $ftp