Net::Server::Mail::ESMTP - A module to implement the ESMTP protocol


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

    my @local_domains = qw(;
    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 some extensions
        # adding some handlers
        $esmtp->set_callback(RCPT => \&validate_recipient);
        $esmtp->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 class implement the ESMTP (RFC 2821) protocol.

This class inherit from Net::Server::Mail::SMTP. Please see Net::Server::Mail::SMTP for documentation of common methods.


ESMTP specific methods.


Activate an ESMTP extension. This method takes a module's name as argument. This module must implement certain methods. See Net::Server::Mail::ESMTP::Extension for more details.


Descriptions of callback who's can be used with set_callback method. All handle takes the Net::Server::Mail::ESMTP object as first argument and specific callback's arguments.


Takes the hostname given as argument. Engage the reverse path step on success. RFC 2821 requires that EHLO command return the list of supported extension. Default success reply implement this, so it is deprecated to override this reply.

You can rebuild extension list with get_extensions() method.


    my @extends;
    foreach my $extend ($esmtp->get_extensions())
        push(@extends, join(' ', $extend->keyword(), $extend->parameter()));
    my $extends_string = join("\n", @extends);


Please, see Net::Server::Mail, Net::Server::Mail::SMTP and Net::Server::Mail::LMTP.


Olivier Poitrey <>


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, 2007 - Xavier Guimard