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Install and Config Psad in Debian 7 Wheezy

Psad (Port Scan Attack Detector) is an intrusion prevention software, written in Perl by Michael Rash. Psad makes use of iptables and ip6tables log messages to detect, alert, and (optionally) block port scans and other suspect traffic. So, logging must be enabled to iptables firewall in order Psad to work.

Additionally, psad can use many signatures from Snort intrusion detection system.

Generally speaking, you do not need psad (not even iptables) if your hosting provider offers a dedicated hardware firewall (for example Cisco ASA 550 series). Of course, you must have the budget to pay for it and the knowledge to setup and manage it.

Install and Config Fail2Ban in Debian 7 Wheezy

Fail2Ban (authentication failure monitor) is an intrusion prevention software, written in Python. Fail2Ban analyzes various services log files (ssh, apache, postfix etc) and if it detects possible attacks (mainly Brute-force attacks), it creates rules on the firewall (iptables and many others) or tcp wrappers (/etc/ hosts.deny) to ban (temporarily or permanently) the wannabe hacker. Simultaneously, fail2Ban informs system administrator with email for its activity in real time.

Some activities which considered as attacks are:

  • multiple attempts for ssh connection using accounts that do not exist in the system
  • multiple attempts for ssh connection switching passwords
  • Apache requests for web pages often requested by bots and scanners.

Debian 7 Wheezy Dedicated Web Server Setup Step by Step

Debian 7.0 Wheezy has been officially released on May 5, 2013. Wheezy is powered by Linux kernel 3.2 and multiarch support. Concerning LAMP software, Apache 2.2.22 MySQL 5.5.30 and PHP 5.4.4 are included. Debian 7 supports systemd.

In this post I describe a dedicated server setup, using Debian Wheezy. It is a Hetzner EX4S dedicated server with IP My blog will be hosted in this server.

I selected a minimal Debian amd64 server (basic Debian system and SSH). Thanks to Hetzner staff, the server was up and running in less than an hour. As usual, they sent me the IP and root password. Below I describe the whole procedure after this point.

Memcached Installation and Configuration with PHP on Debian server

In a previous post I wrote about Memcached installation on Archlinux workstation. This is a similar post for Debian server machine.

I will describe Memcached installation and configuration on a) Debian 6 (Squeeze), the current Debian stable and b) Debian 7 RC1 (Wheezy) with systemd instead of initscripts.

Please, note that Debian 7 RC1 is not recommended for production use. May 5, 2013 announced as release date for Debian 7 (Wheezy).

Memcached Installation and Configuration with PHP on Arch Linux

Memcached is "a free & open source, high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load".

Memcached's APIs provide a giant hash table distributed across multiple machines. Memcached is used from Internet giants as YouTube, Reddit, Facebook, Twitter, Wikipedia and more.

Here is a guide to install and configure Memcached on Archlinux (used as development workstation). In next post I describe Memcached installation on a production Debian server.

Clean Up your CSS code Removing Unused Selectors

If you created your website using a website template, you may not use all the CSS selectors of this template. Moreover, if you use the famous Twitter bootsrtap "framework", many parts of the CSS code probably are not in use.

It is important to remove the unused CSS selectors to speed-up browser rendering of your website. Luckily, there are many tools available to help you in this procedure.

Dust-Me Selectors Firefox extension is my favorite solution, but there are many other solutions.

How to Blend Images using GIMP

GIMP (stands from GNU Image Manipulation Program) is an open source image and photo editing tool. In short, GIMP is the free and open-source alternative for Photoshop, available for almost all operating systems (Linux, Microsoft Windows, OS X).

Image blending is a common task. It can be applied with many ways. Here is a simple example.

According to a recent UN report, more people worldwide have mobile phones than toilets. I want to write an article about this report and I will blend two images to use the result as the article image.

SociaLink: Send and Receive Friend and Follow Requests

SociaLink is a mobile application which aspires to revolutionize the way people network and connect on social media. SociaLink allows two people with the app to friend or follow each other instantly and in-person on Facebook, Twitter, LinkedIn and Instagram.

CEO of SociaLink, Inc., Michael Jacobs, states: "SociaLink is the most efficient way to send and receive friend and follow requests. Have you ever wanted to send friend requests or follow someone without the hassle of search for them? Well now you can! SociaLink is a unique and one of a kind application. Never before have you been able to instantly add your new connections when meeting them in person. Have you ever forgot to get a persons contact information after meeting someone at the bar or a networking event? Don't let this happen to you again!"

Improve your Pinterest Experience in Any Browser

Pinterest is a great place to "collect and organize the things you love" (favourite photos or other media content). As a "visual social network", it is a great source of inspiration. Pinterest was first launched in 2010. During last two years became one of the top 10 largest social networks.

How does Pinterest work? Users can upload images and other media content, known as pins, through collections, known as boards. This functionality is performed using a bookmarklet, known as Pin it button. Additionally, in early March, Pinterest finally launched its own web analytics tool.

Luckily, there are tools, except the default bookmarklet and analytics tools, that can "take off" the experience of using Pinterest, either you are a common user or an Online Marketing Professional.

Migration from initscripts to systemd on Archlinux

systemd is a system and service manager for Linux. It is a replacement for sysvinit. It provides an improved way of booting up the system (allowing more work to be done in parallel at system startup) and also to manage services. "systemd" appears a remarkable adoption from many Linux distributions. Some of them are Fedora, Mandriva, openSUSE, ArchLinux. In Debian and Gentoo systemd is available, but not enabled by default. Inclusion in Red Hat Enterprise Linux 7 is also planned.

In short, except Ubuntu who has developed its own startup manager, almost all the rest distributions will use systemd as system and service manager.

Archlinux included systemd since October 2012. From now, initscripts will be dropped from various packages. Any users still using them should switch to systemd.

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