vincentkong.com

When I flashed my Linksys WRT54GL router last year in July with the DD-WRT v23 SP2, the version has already been around since September 2006.

The default firmware for Linksys has a severe problem where they track old connections for FIVE days, which causes the router to hang when using software that generates a lot of connections.

The DD-WRT v24 was recently released on May 18, 2008 and I was more than happy to flash my router with the new version.

The project comes in 6 different version: Micro, Mini, Standard, VOIP, VPN, Mega. I downloaded and installed the V24_mini_generic.bin as recommended by the Supported Device page. The flashing took about 2 minutes to complete, and all the settings on the router will reset. The default username is “root” and password is “admin” for the DD-WRT control panel.

A week ago my wireless network card died on my IBM Thinkpad T42. I visited the IBM shopping website to look for the Intel Pro/Wireless 2200BG and found it cost approximately $80 not including taxes and shipping. Knowing the price tag was totally unreasonable, I looked somewhere else, and I ended up getting it at Dell for half the price!

After the network card arrived, I immediately replaced the card and booted up my laptop. Next thing I know, I see an error message:

1802: Unauthorized network card is plugged in
Power off and remove the miniPCI network card.


Apparently IBM insists on only accepting “IBM brand” wireless cards through a restriction set in the BIOS. However, there is a fix available for the 1802 error: a DOS program no-1802.com, which will flip a single bit in the CMOS, allowing use of any Mini-PC wireless card.

I disabled the wireless card through the BIOS, to avoid having to physically remove it. Then follow the steps to apply the fix:

1. Download no-1802.com
2. Boot the laptop in DOS mode
3. Run no-1802.com

Nothing happened after running the command, I rebooted the laptop and re-enable the wireless card from the BIOS. The laptop was able to boot without any issues, and I’m able to use my new wireless card successfully!

For better conveniences, I downloaded bootable CD image which allowed me to boot in DOS. A floppy disk image is also available to download as well.

For more information refer to ThinkPad 1802 Error Fix or Problem with unauthorized MiniPCI network card.

Last week I flashed my Linksys WRT54GL router with a 3rd party firmware DD-WRT v23 SP. The installation resolved my issues with the original Linksys firmware of not being able to surf the internet while downloading with bittorrent. However, I found connectivity was still a bit sluggish and at times it was difficult to access the DD-WRT web administration interface.

I found some performance tips related to router slowdown from the DD-WRT Wiki website, and implemented one of the solutions recommended on the page:

• Go to the Web-Admin and log in
• Go to ‘Administration’
• Go to ‘Management’
• Enter the following values at ‘IP Filter Settings’
  • Maximum Ports: 4096
  • TCP Timeout (s): 3600 to 90 (decrease if you have many TCP connections)
  • UDP Timeout (s): 3600 to 90 (decrease if you have many UDP connections)

This weekend, I was assigned to do load testing from my home for a project at work. The load testing involved running with 10 to 20 users, with each user running 2000 iterations. With the number of open connections the load testing will make, I was pretty sure the original Linksys firmware would not be able to handle it, so I was curious on how the DD-WRT firmware would perform.

The results was very promising, after running the load testing for an hour, my network was still running smoothly, and I had no connectivity issues with surfing the internet. I was also, able to download bittorrent and watch streaming video at the same time without experience any latency. I checked the status page of the router and found that the router was experiencing very high load for over a long period of time, as well it had 94% active connections of the available 4096.

Occasionally, I have been having trouble surfing the internet when I’m using bittorrent at the same. In the past, all I had to do was reset the router by unplugging the power. Later, I followed some tips of optimizing my connections and restricted my global connection to under 200. This helped a lot and I haven’t need to reset my router anymore for a while.

For the past 2 weeks the connectivity issue has come back again and reseting the router no longer helps anymore. The only way I can resolve the issue is to power down the boardband modem until I get a new IP address assign to me when it restarts.

I decided to take some risk and install a 3rd party firmware for my router as they are often tuned for higher loads. The two most popular firmwares I found are:

• DD-WRT
• OpenWrt

Both are GNU/Linux based firmware for embedded devices. I decided to try out DD-WRT because it had a better web interface, as well, as of version v23 was completely rewritten and the Linux Kernel is based on the OpenWrt Kernel.

I flashed my router with the standard generic version of v23 SP2 which can be downloaded from their website. The actually flashing was relatively easy, I just did a firmware upgrade using web administration interface from the original Linksys firmware.

One issue I had, was that I wasn’t able to access the web administration interface for DD-WRT after the flashing. However, that was resolved when I hard reseted my router, unfortuntately all my preivous settings was gone after this, but it wasn’t too painful to set everything back up again.

This is a high level overview of what I did to build my server at home.

Hardware for the Server

For my server I recycled an older desktop, which works well since most unix operating systems uses less resources than Microsoft Windows.

Hardware Specifications for My Server:

Building the Server

I decided to build a LAMP (Linux, Apache, MySQL, PHP) platform for my server. For the Linux operating system, I chose Ubuntu because it was very easy to install, provided a lot of documentation online, as well as it had great community support.

Setting up the Network/Router

For the server I manually gave it a static local IP address 192.168.1.100. In my router I enabled port forwarding for ports 80 (for HTTP) and ports 22 (for SSH) to forward to 192.168.1.100.

Registering a Domain Name

To register for a domain name I use GoDaddy because they are currently the cheapest provider that I can find, and domain managing was through their web based interface which makes things really easy.

Setting up Dynamic DNS

My ISP provider provides me with a dynamic IP address, therefore I had to search for a DNS service that provided dynamic DNS support. I registered at ZoneEdit because it provides the service free for up to 5 domains. After successfully registering, ZoneEdit provided me with two name servers which I had to update my domain name to use through GoDaddy.

Setting up Dynamic DNS client

I use ddclient to update my dynamic DNS entries for ZoneEdit. The client is ran as a service which get executed every 5 minutes. When it awakes, it connects to my router and extracts the WAN IP address. If the address has changed then it’ll update my entry in ZoneEdit.

After I finish configuring everything I’m able to connect to my server using the domain name I registered at GoDaddy vincentkong.com. I can now then setup the rest of the services that I want to be available on my server. e.g. Apache, FTP, SSH, SMTP, etc.