{
    $OUT = "";

    use esmith::DomainsDB;
    my $ddb = esmith::DomainsDB->open_ro();

    for my $domain ( $ddb->domains )
    {
        my $mail_server = $domain->prop('MailServer')
                          || $DelegateMailServer
                          || 'localhost';

        next if ( $mail_server eq 'localhost' );

        $OUT .= $domain->key . ":$mail_server\n";
    }
}