Tutorials @ Bitubique

L2TP IPSec server setup for Linux

xiaofeng — Tue, 16 Dec 2008 11:26:38 +0000

Tested under: CentOS 5.2, Ubuntu Intrepid Ibex (8.10), Ubuntu Hardy Heron (8.04), both 32-bit and 64-bit flavors.

Tested working with the following clients: Windows XP, Windows Vista, iPhone, Mac OS X Leopard.

Assumed you are a router / gateway and have a LAN behind it. Once connected, your IPSec client will get your LAN IP.
If you are a standalone server and have only one IP available, use dummy interface (search for dummy.ko) to configure another "virtual LAN" with different IP segment than your server. Configure xl2tpd to give IP from this "virtual LAN" range.

How to enable Time Machine to backup to network disk

xiaofeng — Mon, 08 Dec 2008 15:22:51 +0000

Simple as a pie. Just follow these steps:

Using imapsync to backup / archieve your Gmail emails

xiaofeng — Sun, 10 Aug 2008 01:52:00 +0000

Keep copy of your Gmail somewhere else. You know, in case they turn evil.

1. Download and install the latest version of imapsync at http://www.linux-france.org/prj/imapsync/dist/. As of today, the latest version is 1.255.

ATSServer and mdworker consuming significantly huge amount of CPU resources

xiaofeng — Tue, 01 Apr 2008 07:43:00 +0000

...and caused the Leopard to slow down...

My Mac have 4-core 3.0 GHz CPU with 4 GB RAM, yet this past week or so it seems to slow down to a crawl. Switching applications become sluggish, Dashboard taking its own sweet time to appear, and the CPU meter is constantly showing 100% usage in two of the core.

Replace the anemic Mac clock

xiaofeng — Tue, 01 Apr 2008 03:31:00 +0000

Mac: Spice up your clock with calendar and better customization with MagiCal

In case you haven't notice, the default Mac clock (top-right on the menu-bar), is severely sparse in features, compared to other modern operating system released in 2007-2008. Both Vista and Linux (at least Ubuntu anyway) display a useful monthly calendar with time-zone whenever you click on the clock. And what did you get when you click the default Mac clock? Almost nothing useful. There's only three menus: View as Analog, View as Digital, and Open Date & Time. Duh...

Capture your Mac screen

xiaofeng — Tue, 01 Apr 2008 02:31:00 +0000

Mac: Quick keyboard shortcut to save your screen as image

Command + Shift + 3 -> Capture your whole screen / desktop.
Command + Shift + 4 -> Change the cursor to a crosshair, and allow you to select portion of your screen / desktop you want to capture.

For both keyboard shortcut, the screen capture will be saved to your desktop as a PNG file, with name as Picture 1.png, Picture 2.png, etc.

Remove and rebuild font cache files on Mac OS X

xiaofeng — Tue, 01 Apr 2008 02:25:00 +0000

FontNuke to the rescue!

During my previous investigation to determine why Mac OS X Leopard CPU usage spike up, I've read tips that said clearing up my font caches might help with the problem. So I've set out to search for tools to will help me to do this task, and stumble upon FontNuke.

How to fix "VMware Workstation was unable to claim the device (No such file or directory)"

xiaofeng — Fri, 28 Dec 2007 00:48:00 +0000

Workaround for Workstation 6.0.2 under Ubuntu Gutsy Gibbon 7.10. Most probably would work under different distribution and kernel.

I'm running Ubuntu 7.10 using custom 2.6.23.11 kernel. Somehow, starting from kernel 2.6.23, VMware was unable to properly use my Windows Mobile PDA (Atom O2 Life). Every time I plugged in the Atom, VMware will spurt out "VMware Workstation was unable to claim the device" message. The issue was actually with VMware, and not the kernel. Follow the steps outlined below to work around this bug in VMware.

Accelerate Plone with Varnish

xiaofeng — Sat, 22 Dec 2007 08:28:00 +0000

Speed-up Plone site with Varnish and lighttpd

Introduction

This tutorial highlight the necessary steps to configure Varnish and lighttpd to serve your Plone site. The primary benefit is that you can tremendously improve performance of your Plone. In Bitubique.com case, the stock Plone installation was only able to push up to 13 requests per seconds, but putting Varnish and lighttpd in front push the performance up to 160 requests per seconds. That's 12 times faster than stock installation!

Defragment XFS File-system

xiaofeng — Wed, 12 Dec 2007 10:52:00 +0000

Linux: How to defragment XFS

I have been using XFS file-system for all my Linux box for quite some time now. XFS have some fancy features such as live file-system defragmenting. Let's cover how to do that.

First, make sure you have the xfsdump utilities install. For Ubuntu or its derivatives distribution, simply issue this command:

sudo apt-get install xfsdump

Then, optionally you can check how fragmented your file-system is by this command:

Adding bookmark button to Plone page

xiaofeng — Tue, 11 Dec 2007 07:32:00 +0000

Plone: Tips on how to add bookmarklets to Digg, Del.icio.us, Furl, Facebook, Yahoo Myweb, Reddit, Ask, Live, Stumbleupon, and more.

This is one method which can be used to add bookmarklet that enable viewer of your site to save or bookmark your site to a number of popular bookmark and social network sites. Here goes.

Recovering from stuck modifier keys caused by VMware

xiaofeng — Tue, 11 Dec 2007 06:36:00 +0000

I use VMware a lot, mostly using VMware Workstation 6.0.2 under Linux host. However, from to time, some or all of the modifier keys (Ctrl, Shift, and Alt) somehow ceased to function. Seemed that sometime VMware failed to correctly restore those keys function to X server.
Here's simple command, using xmodmap (installed as part of X base utilities) that will fix this issue. xmodmap is assumed to be located at /usr/bin

Installing and configuring FireHOL

xiaofeng — Tue, 11 Dec 2007 05:09:00 +0000

Linux / Network: Beginners guide to FireHOL

NOTE: Content of this tutorial is probably outdated.

Part 1

Having firewall is one of the steps you can take to make sure that you machine is a little bit secure. This is achieved by opening access only to application or ports that you explicitly allow, and blocking the rest. This for me is a good practice, although some people might argue otherwise.

Using modinfo

xiaofeng — Tue, 11 Dec 2007 03:26:00 +0000

Linux / Kernel: Introduction to modinfo

From Wikipedia:

Starting with SQLite

xiaofeng — Tue, 11 Dec 2007 03:13:00 +0000

SQLite is a small C library that implements a self-contained, embeddable, zero-configuration SQL database engine. The primary benefits of using SQLite is that you can create a self-contained database in your application.

What is so great about this? Well, for starters you can:

Manipulate data inside your program using standard SQL construct.
Zero database configuration – but you get database-like capabilities for your program.