Making changes mutatis mutandis to Net::SMTP::SSL, I "created" Net::POP3::SSL. Then used the test code given below to connect to a pop3 server (using Net::POP3 and Net::POP3::SSL, one at a time). Both attempts succeeded, as shown by the output.

However, both outputs look alike (except for the leading tag)!

What exactly needs to be done in the user-code so that the output would explicitly show ssl'ish things happening in one case and non-ssl'ish things happening in the other case? For example, how would one print out the messages being exchanged by the local machine and the pop server and show that in one case the messages are in plain text and in the other case the messages are ssl-encrypted?

#!/use/bin/perl
BEGIN {(*STDERR = *STDOUT) || die;}
use diagnostics;
use warnings;
use strict;
$| = 1;

{
package Net::POP3::SSL;
# $Id: SSL.pm,v 1.1 2004/07/20 03:22:18 cwest Exp $
use strict;

use vars qw[$VERSION @ISA];
$VERSION = sprintf "%d.%02d", split m/\./, (qw$Revision: 1.1 $)[1];

use IO::Socket::SSL;
use Net::POP3;

@ISA = ( 'IO::Socket::SSL',
         grep { $_ ne 'IO::Socket::INET' } @Net::POP3::ISA );

no strict 'refs';
foreach ( keys %Net::POP3:: ) {
    next unless defined *{$Net::POP3::{$_}}{CODE};
    *{$_} = \&{"Net::POP3::$_"};
}
1;
}

my $pop_host    = '<pop.host>';
my $pop_port    = 995;
my $user_id     = '<user_id>'; 
my $password    = '<password>';

my %pop_options = ( 
                     Host =>       $pop_host, 
                     LocalPort =>  $pop_port, 
                     #ResvPort =>  1,
                     # Timeout =>  30,
                     Debug     =>  4,
                  ); 

my %pop_ssl_options = ( 
                         Host =>       $pop_host, 
                         Port =>       $pop_port, 
                         #ResvPort =>  1,
                         # Timeout =>  30,
                         Debug     =>  4,
                      ); 

test_pop(); 

sub test_pop
{
   my $mail ='';

   if(!($mail = Net::POP3::SSL->new(%pop_ssl_options)))
   #if(!($mail = Net::POP3->new(%pop_options)))
   {
      print "ERROR:  Could not open $pop_host\n$!\n"; 
      return -1;
   }

   my $number_of_messages = $mail->login($user_id, $password);

   if(!$number_of_messages) 
   { 
      (defined $number_of_messages) or print "ERROR:  Login error for 
+$pop_host\n$!\n";
      $mail->quit();
      return -1;
   }
   print "Number of messages:  $number_of_messages\n";
}

__END__

Output:

Net::POP3>>> Net::POP3(2.29)
Net::POP3>>>   Net::Cmd(2.29)
Net::POP3>>>     Exporter(5.60)
Net::POP3>>>   IO::Socket::INET(1.31)
Net::POP3>>>     IO::Socket(1.30)
Net::POP3>>>       IO::Handle(1.27)
Net::POP3=GLOB(0x1d699cc)<<< +OK hello from popgate on pop104.plus.mai
+l.stuff.com 2.38.1
Net::POP3=GLOB(0x1d699cc)>>> USER <user_name>
Net::POP3=GLOB(0x1d699cc)<<< +OK password required.
Net::POP3=GLOB(0x1d699cc)>>> PASS ....
Net::POP3=GLOB(0x1d699cc)<<< +OK maildrop ready, 452 messages (5836296
+ octets) (6062525 3105357824)
Number of messages:  452


Net::POP3::SSL>>> Net::POP3::SSL(1.01)
Net::POP3::SSL>>>   IO::Socket::SSL(1.08)
Net::POP3::SSL>>>     IO::Socket::INET(1.31)
Net::POP3::SSL>>>       IO::Socket(1.30)
Net::POP3::SSL>>>         IO::Handle(1.27)
Net::POP3::SSL>>>           Exporter(5.60)
Net::POP3::SSL>>>   Net::Cmd(2.29)
Net::POP3::SSL=GLOB(0x1d69a0c)<<< +OK hello from popgate on pop106.plu
+s.mail.stuff.com 2.38.1
Net::POP3::SSL=GLOB(0x1d69a0c)>>> USER <user_name>
Net::POP3::SSL=GLOB(0x1d69a0c)<<< +OK password required.
Net::POP3::SSL=GLOB(0x1d69a0c)>>> PASS ....
Net::POP3::SSL=GLOB(0x1d69a0c)<<< +OK maildrop ready, 447 messages (58
+08500 octets) (6034729 3105357824)
Number of messages:  447
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