Remote Desktop Support With VNC

VNC is a well-known tool for remote desktop view and control. The two computers establish a TCP connection so that one of them can access the display of the other. However, almost always these two computers are behind a firewall/router and do not have a real IP to be accessed from the Internet. In such a case one of them can do port forwarding on the router/firewall and this would allow the connection to be established. The problem is that more often than not, none of the parts that want to establish such a remote connection have access to the firewall that separates/protects it from the real internet. Sometimes it can even be several levels deep behind the firewall (several layers of firewalls). However, if you have access to an external server (for example a server in the cloud) there is still a workaround and things can be fixed to work. Here I will explain the tricks and hacks that can be used in such a case in order to establish a secure connection to a remote desktop.

Visualization with gourse

Recently I made this visualization for contributors to https://l10n.org.al for the last two years (2012-2013). This visualization was done with gource. It was a bit of hacking, so I would like to describe here how I did it.

Cloning a B-Translator Server

Why do I need to clone a B-Translator server? An obvious reason is to have a backup server. In case that something goes wrong with the main server I can quickly switch to the backup server, until I find and fix the problem.

A clone can also be used for testing. Before applying something on the main server I can test it first on a clone/backup server.

Another reason for cloning can be load-balancing. It is possible to keep several clone servers synchronised with each-other, and then the work can be shared between them with a load balancer. I haven't tried this yet, but I think that it should work.

It can be possible and even simple to make identical clones just by copying the physical disk or the filesystem. However I prefer to build a new server from scratch and copy only the relevant data from the old server.

Easy Blogging With Emacs

Time after time I write technical blogs and articles that describe and summarise my experiences. Nowadays all the blogging sites and tools offer WYSIWYG editors. And it makes blogging so easy, right? Not for me! I always find WYSIWYG editing tedious and frustrating.

Using Drupal Features In B-Translator

Features are very useful for building Drupal profiles (re-usable applications). They provide a way to capture and save in code the customizations that are done to a Drupal site/application. Here I will describe how I use them in B-Translator.

Development Setup Of B-Translator

B-Translator helps to get feedback about l10n (translations of the programs). It tries to collect very small translation contributions from a wide crowd of people and to dilute them into something useful. It is developed as a Drupal7 profile and the code is hosted on GitHub. Here I describe the development setup and process that I use for this project. Most of the the tips are project specific, however some of them can be used on any Drupal project.

How To Manage Your Own Domain Name Server

In the old times (when men were real men), people used to manage their domains with their own domain name server. There is now a long time since things got easy and sweet. Nowadays you usually rely on the services provided by your ISP for managing your domain, which often means that you do everything from a nice web interfaces.

However there are people (like me) that prefer to do things the old and sweaty way, which means that you install and manage your own name server. I will describe here how I did it for myself. Actually it is not so difficult, if you know some concepts about how DNS works and you have some basic command-line skills.

Dual Boot Puppy Linux With Ubuntu

Puppy Linux is so nice that I always keep it around even if I don't need it. I have a small partition on my laptop where I install different versions of Puppy, and they co-exist with my main Ubuntu (actually Xubuntu) system. The installation is very easy.

How to Setup a WiFi Access Point on Ubuntu

If you have a single wired Internet connection (like in a hotel room) you can create Wireless Access Point with Ubuntu and share the Internet connection among multiple devices. This can be done very easily on Ubuntu (whatch this tutorial: http://www.youtube.com/watch?v=G0FFQVy3RUg) It will create an ad-hoc wifi network. However ad-hoc networks are not supported in some android models, windows mobile, and iOS devices. A more universal solution is to create an Access Point (or Infrastructure, or Hotspot) wifi network. This is a bit more complicated but not so difficult. Here I will describe how to do it.

Solving an interesting algorithmic problem

The second problem on Google CodeJam 2013, Round 1B was interesting: Problem B. Manage your Energy . The obvious solution of trying all the possible cases and combinations would not work, unless the input had very small limits (besides being not so easy to implement).

Exporting Custom Configurations From a Drupal 7 Site

After installing a Drupal7 site, I have made several configurations/customizations over time. Now I would like to export them somehow, in order to load them to another site. But the problem is that I don't remember exactly what I have done. The Features module does not help because you have to tell it exactly what to export, but I don't remember all the changes.

How to find all the modifications in the configuration of a server

I manage a virtual web server in the cloud (https://l10n.org.al) where I have made lots of configurations over time: installing new packages, tweakings for optimization, changes related to security, etc. Now, if I want to build another server that has the same function and purpose as the first one, I don't remember all the things that I have touched and changed. The long and tedious way would be to go over all the installations and configurations again, and still I may miss something.

How to set up a chroot environment for testing

Recently I have suffered a total system destruction in one of my computers. It happened while I was testing a software that I am developing, due to a simple bug. It helped me realize my lack of caution while testing unstable things, and I learned that it is always better to do the testing inside a chroot environment. Chroot’s provide isolation from the rest of the operating system, so that in case of severe errors damage can be mitigated.

Using NGINX as a Web Server for Drupal

Nginx (engine-x) is a web server that is regarded to be faster than Apache and with a better performance on heavy load. The difference is summed up succinctly in a quote by Chris Lea on the Why Use Nginx? page: "Apache is like Microsoft Word, it has a million options but you only need six. Nginx does those six things, and it does five of them 50 times faster than Apache."

Installing a Clonezilla Server

Clonezilla Server is used to clone many computers simultaneously across a network. This is done using a DRBL server and computer workstations that can boot from a network.

The Digital Signature and the X.509/OpenPGP Authentication Models

This article explains what is a Digital Signature, why it is an important part of the Digital Identity, and how it works. Then it describes the authenticity and social problems related to the usage of the Digital Signature. It explains as well the two authentication models, X.509 and OpenPGP, that can be used to solve these authenticity problems. Finally it makes a comparison between these two authentication models and their features and tries to explain why the OpenPGP model is better.

Virtual Machines on a CentOS Host

A powerful rack server can be used as a host for installing lots of virtual machines, and it can be used as a data storage as well. This article will describe how to use such a server, installed with CentOS, as a host for virtual machines.

B-Translator as a Software Engineering Project

The project B-Translator will be presented, trying to illustrate through it some software development/engineering concepts and practices (how they are actually applied in this project).

How to Secure a Ubuntu Server

Recently I purchased a virtual ubuntu server on rackspace. However I have to manage it myself, and this includes first of all taking care for its security. Securing it is very important and is the first thing to be done, since all the rackspace servers have public IP-s and so are open to all the possible attacks from the Internet. Here I will describe some of the steps that can be done to secure the server.

Improving the Performance of a VM by Using a Real Disk Partition

I have used zentyal as a gateway server, and it is actually running on a virtual machine. An important component of it is squid, which is supposed to improve the efficiency of the network connection by saving in cache the web pages that have been already visited, and fetching them from the cache when they are re-visited.

This is an operation that makes intesive usage of the disk, and virtual disks (used on virtual machines) are not particularly efficient for it. However, a virtual machine can also use a real partition, so the efficience of squid can be improved by attaching a real partition to the virtual machine and using it for the cache.