(Perl) 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 Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

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

$ftp = chilkat::CkFtp2->new();

$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() . "\r\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 is a Cert
$cert = $ftp->GetSslServerCert();
if ($ftp->get_LastMethodSuccess() != 1) {
    print "No server certificate!" . "\r\n";
}
else {
    # Display the distinguished name of the SSL cert.
    print $cert->subjectDN() . "\r\n";
}

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

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

$success = $ftp->Disconnect();