Creating Minimal Throw-away CentOS 6 VMs

Whether you are using CentOS for a build server or simply testing out a new configuration, you can quickly create a VM (virtual machine) that is under 1GB. You can do this without downloading any special tools or ISO files — just the CentOS installation DVD and VirtualBox (or VMware if you prefer).

I like the text-based console, so you won’t be getting a GUI or fancy Linux desktop with this one. Given its small size, you could also archive the entire environment (or even several of them) for future use without having to waste gigabytes of free space. These environments also serve as a base which can be upgraded or added onto to provide more functionality later.

Continue reading

Advertisements

Encrypt All the Drives

I have always been an advocate on storage security (all types of security, actually). I like how iOS devices keep all files encrypted, even if you do not set a passcode on the device. They do this to facilitate quick erasure of files on the device — to erase all the data, they simply wipe the master key.

Erasing magnetic storage media isn’t difficult, but it is time-consuming. For solid state media such as SSDs and flash drives, the wear-leveling makes it difficult to ensure that all flash blocks have been securely overwritten. The answer to this is to encrypt everything.

Encrypt all the drives!! (meme)

Recently I have been busy building a Linux-based NAS and I decided to put this to practice.

Continue reading

Implementing EAP-SIM at Home

What is EAP-SIM?

EAP-SIM is one of the authentication methods that can be used in an 802.1x or WPA Enterprise network. Specifically, it relies on the user’s SIM card to process a presented challenge. This has been used by some telcos to provide WiFi service without having to maintain a separate set of credentials. However, not all phones support EAP-SIM.

Phone displaying EAP-SIM as a WiFi authentication method

Since I’m already using a RADIUS setup at home, the use of EAP-SIM will eliminate the need to install my CA certs onto each device. But of course, there is still a fair bit of work to do…

Continue reading

Hacking Functionality into ASUSWRT Routers

This weekend, I spent some time to replace my aged Linksys WRT54G wireless router, which is running DD-WRT. The WRT54G is slow by today’s wireless standards and since I sync my iOS devices wirelessly, the speed was getting quite unbearable. When I bought my Macbook Pro in 2007, it already has draft 802.11n support and fast-forward to 2012, my iPad (1st generation) and iPhone 5 both support the 5GHz band.

The ASUS RT-N56U wireless router ranks up there on wireless performance, and the “feature” I was really after was a router that can run an alternative firmware such as Tomato or DD-WRT. The really good news is, I figured out how to get the functionality I wanted while still using the official ASUS firmware.

ASUS router photo

For proper reviews and better photos, you might want to check out these other reviews:

Read on to find my short review, as well as how you can run your own programs on the router without using a third-party firmware.

Continue reading

SFF Server Build (Part 1): Short Cables

After 10 years, I decided to replace my 633MHz home server with something more modern. The fans on the system were making a lot of noise, especially the Slot-1 CPU cooler fan, which I don’t think I can find a replacement for. Also, the motherboard was very choosy about the power supply, meaning I could not use the newer, more energy efficient supplies; the voltage monitors claim the voltage is out of the acceptable range and refuses to continue beyond the POST screen.

I chose the MicroATX form factor, and the most compact case is the Silverstone SG02F because it places the power supply on top of the board. Most other cases I’ve seen have a similar layout to an ATX tower, but with a height reduction.

The wires are long and unwieldy because they assume you are using a normal ATX case, in which case you need relatively long cables depending on how the case is laid out. However when building a SFF machine like this, it gets really untidy. I decided to reduce the length of the cables.

Here’s the before photo of the wiring – the worst offenders are the SATA cables, the case front panel wires, and the SATA power connector.

Continue reading