Net::Server::Mail(3) Class to easily create a mail server


use Net::Server::Mail::SMTP;
my @local_domains = qw(;
my $server = IO::Socket::INET->new( Listen => 1, LocalPort => 25 );

my $conn;
while($conn = $server->accept)
my $smtp = Net::Server::Mail::SMTP->new( socket => $conn );
$smtp->set_callback(RCPT => \&validate_recipient);
$smtp->set_callback(DATA => \&queue_message);
sub validate_recipient
my($session, $recipient) = @_;

my $domain;
if($recipient =~ /@(.*)>\s*$/)
$domain = $1;
if(not defined $domain)
return(0, 513, 'Syntax error.');
elsif(not(grep $domain eq $_, @local_domains))
return(0, 554, "$recipient: Recipient address rejected: Relay access denied");
sub queue_message
my($session, $data) = @_;
my $sender = $session->get_sender();
my @recipients = $session->get_recipients();
return(0, 554, 'Error: no valid recipients')

my $msgid = add_queue($sender, \@recipients, $data);
or return(0);
return(1, 250, "message queued $msgid");


This module is a versatile and extensible implementation of the SMTP protocol and its different evolutions like ESMTP and LMTP. The event driven object-oriented API makes easy to incorporate the SMTP protocol to your programs.

Other SMTPd implementations don't support useful ESMTP extensions and the LMTP protocol. Their interface design precludes adding them later. So I've decided to rewrite a complete implementation with extensibility in mind.

It provides mechanism to easy addition future or not yet implemented ESMTP extensions. Developers can hook code at each SMTP session state and change the module's behaviors by registering event call-backs. The class is designed to be easily inherited from.

This class is the base class for mail service protocols such as Net::Server::Mail::SMTP, Net::Server::Mail::ESMTP and Net::Server::Mail::LMTP. Refer to the documentation provided with each of these modules.



    $instance = Net::Server::Mail->new( [option => 'value', ...] )


Sets the input handle, from which the server reads data. Defaults to STDIN.
Sets the output handle, to which the server writes data. Defaults to STDOUT.
Sets a socket to be used for server reads and writes instead of handles.
Number of seconds to wait for before printing an error message. This avoids some DoS attacks that attempt to flood the server with bogus commands. A value of 0 turns this feature off. Defaults to 0.
Number of seconds a connection must remain idle before it is closed. A value of 0 turns this feature off. Defaults to 0.


Some commands need to do a job after the handler call. The handler may want to override this to prevent the job from being executed.

By calling this method with a (defined) false value as an argument, the expected job isn't executed. Defaults to true.


  ($success, $code, $msg) = $obj->set_callback(VERB, \&function, $context)>

Sets the callback code to be called on a particular event. The function should return 1 to 3 values: (success, [return_code, [``message'']]).

        'RCPT', sub
            my($address) = @_;
                # default success code/message will be used
                return 1;
                return(0, 513, 'Relaying denied.');



Start a new session.


Send the introduction banner. You have to call it manually when are using process_once() method. Don't use it with process() method.



Append at the opening of a new connection.

Handler takes no argument.


This event append where timeout is exceeded.

Handler takes no argument.


This event append where connection is closed or an error occurs during reading from socket.

Takes the error description as an argument if an error occurred and the argument is undefined if the session was closed by peer.

        'stop_session', sub
            my($session, $err) = @_;
            if( defined $err )
                print "Error occurred during processing: $err\n";
                print "Session closed py peer\n";
            return 1;


Olivier Poitrey <[email protected]>


Available on CPAN.

anonymous Git repository:

git clone git://

Git repository on the web:



Please use CPAN system to report a bug (


This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA


Copyright (C) 2002 - Olivier Poitrey
Copyright (C) 2007-2013 - Xavier Guimard


Copyright (C) 2009 - Dan Moore <dan at>
Copyright (C) 2013 - Mytram <[email protected]>
Copyright (C) 2013 - Xavier Guimard <[email protected]>


2012 - Georg Hoesch (patch to reduce memory consumption)