Hi,

I recently worked with a WordPress MU installation.  As an ease of deployment and probably because it is largely used on shared hosting which may not offer access to cron jobs, WordPress default way of processing its scheduled tasks is through front-end and admin page requests.  As a result, everytime a page is requested, the system looks to see if there are jobs to run.  When so a call is performed to execute the tasks.  The asynchronous nature of the call makes it somewhat transparent from the webuser perspective.

Although it works well, I do not feel confident to use this mechanism on a site with a lot of traffic.  After some google searches to find out how it works, I’ve read many stories about hosting companies denying access to wp-cron.php because of bad impact on their server.

I had another issue while using WP-SuperCache.  Since the super cache is super because it prevents loading the whole PHP engine for guest requests.  Unfortunately, no php code execution means no cron execution for super cached pages… Since the cron is responsible of cleaning the super cached files, they are served indefinetly or until a user logs in (logged users do not get super cached files).

So for all the good reason I had, I wanted to run WordPress cron jobs from a real cron schedule.

Read the How-To on next page

Quick Links:

• Installation Steps
• Hardware Compatibility List

Opinion:

In my quest for learning, I did my first step with Linux back into 2006 with the 6.06 LTS version.  Since that time, I have learned quite a lot, but still consider myself a newbee.

From that perspective, Ubuntu has come long way.  Every 6 months, since Ubuntu 6.10, I have tested each release. In general it was always a step forward for user friendlyness.  Ubuntu 8.10 is no exception…  and in my opinion it is the best Ubutu release ever.  Ubuntu Intrepid Ibex is somewhat what I was expecting from 8.04.

The new artwork makes it feel different than previous release.  While exploring the menus and configurations you will notice that it is not just a feeling.  In the past, to configure a wireless network, you had to go to System / Administration / Networking.  Then setting your WEP key (if using WEP) and activate the adapter.  Often I had to perform “activate+deactivate” a couple of time to finally get a working connection.

Now the network manager can be found under System / Preferences / Network configuration, but I didn’t have to go there since a tooltip appeared at first logon stating “wireless networks available”.  I just had to select the right SSID and configure the WEP key from there.  On top of that, the connection was established within seconds after first try…

Peoples definition of “home computer” has changed quite a bit.  Previously, home computer was synonym of desktop PC, now if notebooks sales have not exceeded desktop sales, I guess it is just a matter of time…  I think, with this release, Ubuntu followed this wave of mobility.

2 comments

When you have a home server, you may not have the chance to be connected to the Internet using a static IP address, instead your IP address is a lease from your Internet Service Provider and may change every day depending on the setup.

So when you are in the outside world, it is not possible to guess the IP address of your computer, how could you connect to it if you wanted to?  The solution is to use a dynamic DNS forwarder like DynDNS.org.  Talking about DynDNS, many standard firmwares (Netgear, Linksys, etc.) support updating your IP when it changes.  Since I use Tomato firmware, I will explain how to configure it.

• First, you must register on DynDNS.org by creating an account.
• Then go into the “My Services / Host services” section of the site and add a new host name
• The free service offers you to choose any sub-domain name from their available list.
  (ex: myhostname.getmyip.com, myhostname.kick-ass.net)
• So you have to enter:
  • the name you want (myhostname)
  • the domain name (kick-ass.net)
  • if you want to enable wildcards
    (if enabled, anything.myhostname.kick-ass.net will be forwarded as well)
  • the service type: Host with IP address
  • leave the IP address, Tomato will update it automatically
  • leave the mail router checkbox unchecked

  
• create that host…

• Now you have to configure Tomato
• Navigate to the router’s web administration
• Open up the page under Basic / DDNS.
• Tomato offers to configure up to 2 host names, let’s fill the first one:
  • IP Address: Use WAN IP xxx.xxx.xxx.xxx (recommended)
  • Service: DynDNS – Dynamic
  • Username: your account name
  • Password: your account password
  • host name: myhostname.kick-ass.net

  

****** UPDATE 2009/01/12

Fix on the port numbers used as example.  Port numbers must not be bigger than 65535. 

Thanks Mike for noting this.

************************

First of all, for simplicity, let’s assume we have a desktop at home that we want to connect to (control remotely) using a laptop while we are at a friend’s home. We will use Remote Desktop to connect from the laptop to the home desktop. The home network is behind a router (firewall) compatible with Tomato (ex: Linksys WRT54GL).

Remote Desktop is a server application that uses TCP/IP network to enable remote control of a machine. It opens the port 3389 to handle network communications. By default Remote Desktop is disabled on Windows XP.

How to enable Remote Desktop on Windows XP (on the home desktop):

Start the system properties in the Control Panel (or right click “My Computer” and click properties). Go to the “Remote” tab. Enable remote desktop by checking “Allow users to connect remotely to this computer”. Note 1: Don’t forget to set a password on the user you intend to use to connect remotely because Remote Desktop will prevent connection with blank passwords. Note 2: By defaut, only users with the administrative priviledges are allowed to connect remotely.

At this point, Windows can handle remote connections.  In order to do it through the Internet you could simply forward the port 3389 from your router to the actual machine but at the same time you would expose your machine to the whole world. If you can do it, somebody else can try too.

Instead, we use a 3rd party firmware (called Tomato) on the Linksys router. This firmware allows us to connect using SSH (a secured command line shell).

With SSH we can create encrypted communication links (called Tunnels) between the laptop and the router. SSH protocol requires a server that will also open a listening port. We need to login to this server to establish the SSH connection and create tunnels.

Why this instead of just opening Remote Desktop port (3389)?

• Because we will use a *different password* (will we? well we should… and a strong one!) than the one on your computer.
• If we would have multiple computers to remote desktop to, we wouldn’t need to open additional ports, just create additional tunnels instead.
• If somebody cracks our router password, he is still limited in he can do, he has to guess/find our machine and crack its password.
• We can make SSH connection more secured by using a key file. This file is needed to establish the connection link, so another level of difficulty for a pirate…
• The communication is encrypted between the two ends of the Tunnels (more privacy)

So how to enable the SSH Server on the Tomato firmware?

Login to Tomato’s web interface Go to Administration / Admin Access In SSH Deamon section, set the following : Enable at startup: checked Remote access: checked Remote port: <choose one> (ex: 5555 — used from Internet) Port: 22 (used from inside the LAN) Authorized Keys: <empty> (for simplicity of this post) Note: Even if the screenshot shows this, we should use a different port than 22 (or 2222). If somebody discover our machine using a port scanner, he will have to guess what is the protocol (is it SSH, RDP, HTTP, FTP, etc?). If we leave the default, the guess is easy.

The home computer is enabled for remote desktop and the router is configured for SSH. Now we need to establish the SSH connection/tunnels, so put the laptop on the backpack and let’s ride to our best friend! Since the laptop is also running Windows XP, we are going to use PuTTY, an open source SSH client software (download it here).

Let’s configure PuTTY:

Start PuTTY and fill the information of the first tab: Host name or IP Address: <enter yours> Port: <the port you set earlier> (ex: 5555)

Configure tunnels in Connections / Tunnels tab: Enter a source port: <choose> (ex: 15338) Enter a destination address and port: <ip>:<port> (ex: 192.168.1.15:3389) Local: Checked Auto: Checked Click add button Note: The destination address and port is the address of our home desktop which is often in the range of 192.168.x.x depending on the router.  Our Linksys uses 192.168.1.x range by default.  IP address could be anything within the range when address is assigned by a DHCP server.  To make sure the desktop computer always have the same IP address, we can set a fixed address or configure Tomato DHCP server to always assign the same (see this post)

When we are going to open the SSH connection, PuTTY will open a local port defined by “source port”.  All the communication to that port will be encrypted and forwarded on the LAN to the destination address and port specified (ex: 192.168.1.15 port 3389).

Now let’s login to SSH Server

Click the Open button, a black screen should appear. We now have to enter the router’s username and password

The only step left is to run Remote Desktop Connection software on the laptop:

Open up remote desktop and specify the computer: localhost:<source port> (ex: localhost:15338) Click connect

Voilà  we are now controlling the home desktop from outside the house using the laptop!

Specifications of the software used in this post:

Since I may not always be on the same machine or with the same operating system when I want to run a virtual machine I bring with me, I store them on a Western Digital MyPassport USB Drive.  This drive is formatted using the NTFS file system.  I had a problem when I first tried to run one using VMWare Server on Ubuntu 8.04.  The virtual machine would not start and it didn’t gave me an error.  Fortunately I found this blog post (Lornajane) that talked about a setting to put in the vmx file of the virtual machine:

mainMem.useNamedFile=”FALSE”

This worked perfectly for me too

Hi,

I’ve been using 3rd party firmware for my Linksys WRT54GL router for some time.  I’ve used DD-WRT, OpenWRT and finally Tomato.   I switched from DD-WRT (for a reason I can’t remember) to go with OpenWRT.  I learned a lot on OpenWRT and really like their Kamikaze version.  The work they did for making it more like a standard distribution (no more NVRAM variables) is really cool.  Finally I recently moved to Tomato because of the lack of User Interface of OpenWRT (Yes I could use X-WRT but I tried it before and prefered to explore Tomato…).  When I feel lazy I prefer to use a GUI than go to the CLI…

Now that I am more familar with my WRT (thanks to OpenWRT and all its documentation), it has been pretty easy to configure Tomato (firmwares are different, but in the end, they often use the same tools… busybox, dnsmasq, etc.).  I have some specific needs that drove me to install a 3rd party firmware in the first place:

1. I need to be able to access my computers from the internet using remote desktop

2. But I don’t want to leave my computers open all day long for nothing, so I need to be able to use Wake-On-Lan to power them up remotely

3. I don’t want to open remote desktop port (3389) on the firewall

4. I want to use DHCP server, but I need to set some specific address (static DHCP) on some computers
   (so port forwarding is always configure correctly for my P2P machine…)

5. I need to be able to use the same domain name (ex: mysite.dyndns.org) with my laptop no matter if I connected to my LAN or to a public network (through the Internet)

My Solution:

*** UPDATE 2008/11/28 ***

See a more complete review of Ubuntu 8.10 on this Lenovo R61 here

***************

General Hardware Specifications of Lenovo R61

Special Keyboard Keys

Installation Steps

The installation steps are the same that I used when I installed Ubuntu 7.10 on my Inspiron 8600

see additional configuration and conclusion on following page >>

Hi,

After playing a lot with multiple Linux distributions, I had hard time make my wireless card working. This was back to the release of Ubuntu 6.06. My wireless card was a Dell TrueMobile based on the Broadcom chip. Broadcom is known to not release chip specifications, so at that time, I had to use the just released open source driver built using clean-room reverse engineering, or rely on NdisWrapper to run the native Windows driver. I managed to make the open source driver work but it was painful: Needed to reconnect repetitively to get a “B” (11 mb/s) connection while my card could go “G” (54 mb/s).

Finally I got tired of all this… Since the Inspiron is using a mini-PCI card for the wireless card, I looked for a replacement card that was working well with Linux and found the Intel PRO/Wireless 2915ABG for less than 50$ CDN. After installation, it worked flawlessly!

If you are tired of you TrueMobile (or Broadcom based) wireless card and you want to replace it, here are the steps:

Oh, by the way, if you follow these steps… remember that your doing it at your own risk! First, it is suggested to ground yourself. You can use an anti-static wristband like this Belkin. Turn your Inspiron on the back and identify the battery and Wi-Fi compartment.
Turn your Inspiron on the back and identify the battery and Wi-Fi compartment. Remove the battery
Once the battery is removed and the Wi-Fi compartment is opened…
Now we need to remove the old Dell TrueMobile wireless card. Gently unplug the two antennas represented by the red circles on the picture beside. (click on the picture for a bigger display) Then press outwards on the little metal clips (blue circles on the picture) holding the wireless card in its socket and it will pop out at a 45 degree angle.
Install the new card by holding the card at a 45 degree angle and slide into the socket. Push down the card and snap it into place alongside the metal clips. Replug the two antennas (see picture beside). Screw the panel back to close the Wi-Fi compartment. Put the battery back in place. If you are using Windows, install the new drivers. For Linux, it should automatically detect it. Enjoy!

Here is a series of posts from ScottGu’s blog about the new ASP.NET MVC Framework.  That seems pretty interesting…

• Part 1 – Introduction
• Part 2 – URL Routing
• Part 3 – Passing ViewData from Controllers to Views
• Part 4 – Handling Form Edit and Post Scenarios

Migrating subversion from a Windows installation to a Linux installation is not just copying the repository structure and files. But it is still quite easy. Here are the steps:

1. Extract the repository data from Windows repository and store it into an OS independant format using the dump command:

   svnadmin dump [repo location] > [dump file]
   ex: svnadmin dump /svn/MyProject > c:\temp\MyProject.dmp

2. Upload the exported file on the Linux system.
3. Create a Subversion repository:

   svnadmin create [repo location]

4. Adjust security settings on the new repository directory (if necessary).
5. Restore the dump file into the new repository:

   svnadmin load [repo location] < [dump file]

Here is an example of loading a dumped file into a Subversion installation for accessing through Apache2 and Ubuntu Server 7.04:

1. create repository:

   sudo svnadmin create /var/svn/MyProject

2. change owner:

   sudo chown -R www-data:www-data /var/svn/MyProject

3. change security:

   sudo chmod -R g+ws /var/svn/MyProject

4. Load dump file:

   sudo svnadmin load /var/svn/MyProject < ~/MyProject.dmp