When you hotplug a hard drive in a virtual machine, the drive do not show in fdisk -l output until you reboot your VM.
In order to get the drive to appear, the SCSI bus need to be rescanned.

this tutorial will explain how to use a MySQL backend in order to authentication users against your Apache website.

To achieve this we will use Apache2 and its auth_mysql module.

Vyatta is a Linux based distro that ease the set up of VPN, Routers, antivirus.... It has a really small footprint on your system as it only requires something like 800M to be installed and is based on Debian. On the top of that, it offers configuration wrappers to facilitate service settings.

This tutorial will explain how to set up 2 Border Gateway Protocol (BGP) boxes to route the traffic from one Autonomous System (AS) to the other using Vyatta.
Vyatta Community Edition 4.1.4 was used during this set up.

Bazaar (bzr) is a distributed version control system (VCS) sponsored by Canonical and thus bzr is widely used by the Ubuntu community.

Like any vcs, bzr will let you track the different version of your code locally and let you push the changes to a remote server.

One cool feature of bzr is that you can maintain a remote copy of your code history without having a bzr server running, nor having a copy of bzr on the remote server running and simply by using ssh to transport the data.

This tutorial will not explain how bzr works, but will show the couple few step to create your local repository, add a few files, commit the changes, push them to a remote server and copy the branch newly created to another machine.

Even though new distros installers tend to support filesystem encryption out of the box, most of the time, it might be interesting to actually understand how it works, mainly when it happens that your system fails to boot :).

Most literature found on the Internet tend to cover how to set up LVM over a partition encrypted with LUKS, this tutorial takes another approach and will explain how to create LUKS encrypted partitions over LVM. The reason for this.... I wanted to have unencrypted partitions :D.

syslogd is the Linux system logging utility that take care of filling up your files in /var/log when it is asked to.

On a standard system, logging is only done on the local drive. But syslog can be configured to receive logging from a remote client, or to send logging to a remote syslog server.

Some of the use cases could be:

• A machine which filesystem goes read-only
• Log replication

this tutorial will explain how to set up both the server, to receive message from a remote client, and the client to emit messages to a syslogd server.

Linux is a perfect platform to act as a router/gateway.

In this tutorial, I will explain how to set up a Linux box to operate as a network router. The box will provide the following services:

• DHCP server to provide the ip addresses to the machines in the LAN
• DNS server to resolve domain names
• Gateway with IP tables to give access to the Internet.
• Firewall with IP tables.

The resulting machine will have quite a small footprint: about 600M, and except if your network is intensively used, a low spec computer can be recycled to do the job.

As the machine is going to operate as a router/firewall

When copying files over the network, the files informations can be modified.

When using cp, one can avoid this issue by using the -a which will do the copy in archive mode, meaning that it will keep the links, preserve mode, ownership and timestamps and the copy is recursive.

the solution to this over the network is rsync alongside with ssh.

The Intel wireless card 4965 AGN does not work properly on ad-hoc networks since hardy and kernel 2.6.24 or around, network-manager can't get it to use the mode ad-hoc and a standard configuration like:

$ sudo iwconfig wlan0 essid myessid mode ad-hoc channel X key s:mykey13charss
$ sudo dhclient wlan0

will fail to get an ip except a long battle at dhclient'ing around.

I managed to get a process to get things working faster.

In the 2 previous articles, I explained how to set up a serial console on Ubuntu and Debian.

This tutorial will now show how to connect to those serial console using another machine using a software called minicom.