Dandello has asked for the wisdom of the Perl Monks concerning the following question: 

#!/usr/bin/perl
use strict;
use warnings;
use Net::SMTP::SSL;
use English '-no_match_vars';

our @ARGV = ( 'mygmail@gmail.com', 'mypassword', 'touser@forumsoftware
+.com', 'mygmail@gmail.com' );
my $body = "Test message";
my $headers = "Content-Type: text/plain\r\n\r\n";
my $smtp_server = 'smtp.gmail.com';
my $port = 465;

my $mailer = new Net::SMTP::SSL(
    $smtp_server,
    Hello => 'mydomain.com',
    Port => $port,
    Debug => 1,
    layer=> 'ssl',
    ) || die "Unable to create Net::SMTP::SSL object. Server: '$smtp_s
+erver', port '$port'\n\n" . $OS_ERROR;
$mailer->auth($ARGV[0], $ARGV[1]);
$mailer->mail($ARGV[3]);
$mailer->to($ARGV[2]);
$mailer->data();
$mailer->datasend("Subject: SMTP SSL test\r\n\r\n" . $headers . $body)
+;
$mailer->dataend; 
$mailer->quit;
exit();

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This isn't creating the new Net::SMTP::SSL object - so of course it fails. But even with Debug on, I'm not getting back anything that tells me why it's failing. I've got a version of this using Net::SMTP::TLS and it connects fine to gmail. But I'm missing something with the SSL version. (I do have a valid SSL Cert for the actual domain this script is installed at.) This is driving me batty.

Replies are listed 'Best First'.
Re: Net::SMTP::SSL ACK!!
by hippo (Archbishop) on Jan 29, 2016 at 11:45 UTC

    I will share with you the ultimate wisdom of SSL/TLS debugging. Anytime you find yourself saying, "why has my SSL/TLS session failed to be established?", all you need to do is insert this line at the top of your script (before any other modules are loaded):

    use IO::Socket::SSL qw(debug3);

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    This will give you a trace of the attempted establishment of the SSL/TLS session and will give at least some clue as to where the error lies. As often as not it will be "certificate verify failed" and you'll need to examine the certs carefully to see why but at least it will give that clue as to where to start looking.

    I hope that this is useful to you.

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      Thanks: This is the Debug trace 
      DEBUG: .../IO/Socket/SSL.pm:1653: new ctx 143739952
DEBUG: .../IO/Socket/SSL.pm:363: socket not yet connected
DEBUG: .../IO/Socket/SSL.pm:1328: IO::Socket::INET6 configuration fail
+ed error:00000000:lib(0):func(0):reason(0)

DEBUG: .../IO/Socket/SSL.pm:1690: free ctx 143739952 open=143739952
DEBUG: .../IO/Socket/SSL.pm:1698: OK free ctx 143739952

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      Now off to figure out what this: DEBUG: .../IO/Socket/SSL.pm:1328: IO::Socket::INET6 configuration failed error:00000000:lib(0):func(0):reason(0) means... Okay, I think I know that the problem is - there IS a problem with the SSL certs and it no doubt relates to the fact that you can have only 1 working https domain per IP address.
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        This looks for me not like a problem at the SSL level but at the plain socket level, i.e. that the TCP connection to smtp.gmail.com port 465 already fails.
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        #!/usr/bin/perl
use strict;
use warnings;
use Net::SMTPS;
use CGI::Carp qw(fatalsToBrowser);
use English '-no_match_vars';

our @ARGV = ( 'me_at@gmail.com', 'mypassword', 'tosombody@forumsoftwar
+e.com', 'me_at@gmail.com' );
my $body = "Test message";
my $headers = "Content-Type: text/plain\r\n\r\n";
my $smtp_server = 'smtp.gmail.com';
my $port = 587;
my $ssl = 'starttls';   # 'ssl' / 'starttls' / undef

my $mailer = new Net::SMTPS(
    $smtp_server,
    Hello => 'host.mydomain.net',
    Port => $port,
    Debug => 1,
    doSSL => $ssl,
    ) || die "Unable to create Net::SMTPS object. Server: '$smtp_serve
+r', port '$port'\n\n" . $OS_ERROR;
$mailer->auth($ARGV[0], $ARGV[1]);
$mailer->mail($ARGV[3]);
$mailer->to($ARGV[2]);
$mailer->data();
$mailer->datasend("Subject: SMTP test\r\n\r\n" . $headers . $body);
$mailer->dataend; 
$mailer->quit;
print "Content-type: text/html\n\n" or croak 'cannot print line1';
print "Complete";
exit();

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        Okay - the above works (and it's not Net::SMTP::TLS). Yes, I know Net::SMTPS is also old and deprecated BUT I found another complication last night. CPanel still ships with Perl 5.8.8 so my code has to work with Perl 5.8.8

        Another annoyance - The docs for Net::SMTP 3.03 say this: 

        B<Port> - port to connect to.
Default - 25 for plain SMTP and 465 for immediate SSL.

B<SSL> - If the connection should be done from start with SSL, contrar
+y to later
upgrade with C<starttls>.
You can use SSL arguments as documented in L<IO::Socket::SSL>, but it 
+will
usually use the right arguments already.

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        But that requires at least IO::Socket::SSL 2.007 and that is well above the version 1.79 that Perl 5.8.8 seems to support. Or at least above the version that I can get CPanel to install.

        So, any hints on how to explicitly tell Net::SMTP 3.03 that it's supposed to tell IO::Socket::SSL 1.79 to start starttls.

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