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.

Download Chilkat Perl Module

use chilkat;

$ftp = new chilkat::CkFtp2();

#  Any string unlocks the component for the 1st 30-days.
$success = $ftp->UnlockComponent("Anything for 30-day trial");
if ($success != 1) {
    print $ftp->lastErrorText() . "\n";
    exit;
}

$ftp->put_Hostname("ftp.myftpserver.com");
$ftp->put_Username("myUsername");
$ftp->put_Password("myPassword");

#  Establish an AUTH SSL secure channel after connection
#  on the standard FTP port 21.
$ftp->put_AuthSsl(1);

#  The Ssl property is for establishing an implicit SSL connection
#  on port 990.  Do not set it.
$ftp->put_Ssl(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:
$ftp->put_RequireSslCertVerify(1);

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

#  Connect and login to the FTP server.
$success = $ftp->Connect();
if ($success != 1) {
    print $ftp->lastErrorText() . "\n";
    exit;
}
else {
    #  LastErrorText contains information even when
    #  successful. This allows you to visually verify
    #  that the secure connection actually occurred.
    print $ftp->lastErrorText() . "\r\n";
}

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

$cert = $ftp->GetSslServerCert();
if ($cert eq null ) {
    print "No server certificate!" . "\n";
}
else {
    #  Display the distinguished name of the SSL cert.
    print $cert->subjectDN() . "\n";
}

print "Secure FTP Channel Established!" . "\n";

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

$ftp->Disconnect();