NAME

       Net::Server::Mail::ESMTP::XFORWARD - A module to add support to the XFORWARD command in
       Net::Server::Mail::ESMTP

SYNOPSIS

           use Net::Server::Mail::ESMTP;

           my @local_domains = qw(example.com example.org);
           my $server = IO::Socket::INET->new( Listen => 1, LocalPort => 25 );

           my $conn;
           while($conn = $server->accept)
           {
               my $esmtp = Net::Server::Mail::ESMTP->new( socket => $conn );

               # activate XFORWARD extension if remote client is localhost
               $esmtp->register('Net::Server::Mail::ESMTP::XFORWARD')
                  if($server->get_property('peeraddr') =~ /^127/);
               # adding some handlers
               $esmtp->set_callback(RCPT => \&validate_recipient);
               # adding XFORWARD handler
               $esmtp->set_callback(XFORWARD => \&xforward);
               $esmtp->process();
               $conn->close();
           }

           sub xforward {
               my $self = shift;
               # Reject non IPV4 addresses
               return 0 unless( $self->get_forwarded_address =~ /^\d+\.\d+\.\d+\.\d+$/ );
               1;
           }

           sub validate_recipient
           {
               my($session, $recipient) = @_;
               my $domain;
               if($recipient =~ /\@(.*)>\s*$/)
               {
                   $domain = $1;
               }

               if(not defined $domain)
               {
                   return(0, 513, 'Syntax error.');
               }
               elsif(not(grep $domain eq $_, @local_domains) && $session->get_forwarded_addr != "10.1.1.1")
               {
                   return(0, 554, "$recipient: Recipient address rejected: Relay access denied");
               }

               return(1);
           }

DESCRIPTION

       When using a Net::Server::Mail::ESMTP script inside a MTA and not in front of Internet,
       values like client IP address are not accessible to the script and when the script returns
       mail to another instance of smtpd daemon, it logs "localhost" as incoming address. To
       solve this problem, some administrators use the XFORWARD command. This module gives the
       ability to read and store XFORWARD information.

   METHODS
       These methods return the values set by the upstream MTA without modifying them so they can
       be set to undef or "[UNVAILABLE]". See Postfix documentation for more.

       •   get_forwarded_values : returns a hash reference containing all values forwarded (keys
           in lower case).

       •   get_forwarded_name : returns the up-stream hostname. The hostname may be a non-DNS
           hostname.

       •   get_forwarded_address : returns the up-stream network address. Address information is
           not enclosed with []. The address may be a non-IP address.

       •   get_forwarded_source : returns LOCAL or REMOTE.

       •   get_forwarded_helo : returns the hostname that the up-stream host announced itself. It
           may be a non-DNS hostname.

       •   get_forwarded_proto : returns the mail protocol for receiving mail from the up-stream
           host. This may be an SMTP or non-SMTP protocol name of up to 64 characters.

SEE ALSO

       Net::Server::Mail::ESMTP, <http://www.postfix.org/XFORWARD_README.html>

AUTHOR

       Xavier Guimard, <x.guimard@free.fr>

COPYRIGHT AND LICENSE

       Copyright (C) 2006 by Xavier Guimard

       This library is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself, either Perl version 5.6.4 or, at your option, any later version of
       Perl 5 you may have available.