Dec 062010

This time i’ll show you how to randomize your smtp outbound’s IP addresses. This can be done via transport map. But, since ordinary Postfix lookup tables store information as (key, value) pairs. it will provide static value only. we need someting that can manipulate the value (right hand side) of a lookup table. In order to answer random transport value.

first come to mind was tcp_tables, tcp_tables lookup table gives some flexibility for us to execute our tiny perl script that will randomizing transport. that’s the basic idea.

Ok, here’s the first part, create perl script call, anyway this script only provide answer in “catch-all” manner. so it will randomized, all outgoing mail.

# cd /etc/postfix
# vi
#!/usr/bin/perl -w
# author: Hari Hendaryanto <hari.h -at->

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

# our transports array, we will define this in as transport services

our @array = (

# Initalize and open syslog.

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

while (<>) {
        # randomizing transports array
        my $random_smtp = int(rand(scalar(@array)));
        if (/^get\s(.+)$/i) {
                print "200 $array[$random_smtp]\n";
                syslog("info","Using: %s Transport Service", $random_smtp);

	print "200 smtp:";

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Mar 262010

This tutorial will covering common feature in git repository

  • commiting via ssh
  • Enable gitweb for web access
  • cloning anonymously using the Git protocol

Install git, git-daemon

# yum -y install git git-daemon gitweb

Create a git user/group

# useradd -U -d /var/cache/git -s /usr/libexec/git-core/git-shell git

Make sure the permissions of the directory are correct

# cd /var/cache
# chown -R git:git git
# chmod 755 git

We’ll be using SSH keys for authenication, so collect the public keys of all the users who need commit access. Then, put the public keys into the right place

# cd /var/cache/git
# mkdir .ssh
# chmod 700 .ssh
# touch .ssh/authorized_keys
# chmod 600 .ssh/authorized_keys
(Put the public keys into authorized_keys, one per line)
# chown -R git:git .ssh/

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