Jul 202011

I have not had time to do the test “postfix memcached patch” because there are no idle servers that can be used for the experiment. instead, I’ve made a tutorial how to integrate memcached as a “postfix lookup table” with the help of tcp_table and a simple perl script.

Indeed, tcp_table “table lookup protocol” is one of the most powerful tools as well as the regexp and pcre, in my opinion. although client-server connection is not protected and and the server is not authenticated.

yes, I did a lot of experiments using tcp_table and perl scripts. it made me realize that I can do almost everything I need and make postfix as my favorite MTA.

Things required:

OK, first we create a simple perl script that allows you to handle the protocols of tcp_table. let’s call it memc.pl

use strict;
use warnings;
use Sys::Syslog qw(:DEFAULT setlogsock);
use Cache::Memcached;

# Configure the memcached server
my $memd = new Cache::Memcached {
            'servers' => [ '' ],

# Initalize and open syslog.

sub qrymemc {
        return unless /^get\s+(.+)/i;
        my $kmemc = lc($1);
        my $vmemc = $memd->get($kmemc);
        if (defined $vmemc) {
                return ($kmemc,$vmemc);

sub trim{

# Autoflush standard output.
select STDOUT; $|++;

while (<>) {
        if (/^get\s+(.+)/i) {
                my $data = lc($1);
                my @res = qrymemc($data);
                syslog("info","data: %s", $data);
                if (@res) {
                        print "200 $res[1]\n";
                        syslog("info","Found: key = %s, value = %s", $res[0], $res[1]);
        print "200 DUNNO\n";

Continue reading »

Oct 032009

I got good workaround for balancing smtp outgoing from postfix mailing list archives(not using expensive real load balancer). suppose we have 4 smtp servers for outgoing email, and we need to configure/load balance like this:

                                                         |            |
                    +----------> smtp backend a -------->|            |
                    |                                    |            |
clients --------> smtp lb -----> smtp backend b -------->|  Intenet   |
                    |                                    |            |
                    +----------> smtp backend c -------->|            |
                                                         |            |

Here’s the configuration :

Continue reading »