Serial over LAN, or SOL for short, is a great tool for diagnostics. Combined with IDE redirection, or IDER, there’s a tremendous amount of things you can do remotely to manage clients. One of the areas where SOL can be helpful is for delivering status updates for IDER boot images that use a graphical interface. Instead of asking someone to read what’s on the screen to you, you can have a clear picture of what’s going on.

The key to this is to include the SOL driver in your live CD boot image. The actual process of including this driver will vary depending on the live CD tools you are using. I won’t go into specific details on the steps needed to include the driver in this post. The popular live CD tools, such as the Windows AIK, have a lot of information available on how to include drivers.

Once you have the SOL driver included in your live CD you can begin to take advantage of the SOL interface by sending text output to the SOL serial port. In most cases the port is COM3, but it may be on another COM port. You will need to do some testing to see which COM port your hardware platforms use for SOL.

Here’s one common scenario where this can be very handy. Let’s say you have a live CD that includes an in-band remote access tool, like PC Anywhere or a VNC server. You can include a startup script that echo’s out the computer’s hostname and IP address information to COM3. That way, you will know when the live CD has booted and the information it may have registered with DNS/DHCP. If you are using a Windows based live CD all you need to do is include commands like this:

echo %computername% >com3

ipconfig >com3

You can even incorporate some ANSI control codes to control formatting. For instance, if you want to have the remote SOL terminal clear it’s screen, you can send the Esc+[2J. The trick is generating the “Esc+” part. In order to do this in Windows, you need to hold down the Alt key, press 0027 on the ten key pad (make sure you include the two zeros) and then let the Alt key go. Unfortunately, Notepad does not seem to support this functionality. As an alternative, I recommend using Notepad++. Once you are done, you should have something like this:

echo ^[[2J >com3

Note: The escape character may appear as "^[" or something else altogether, like a little arrow or block character.  It depends on your OS and application.

 

Here’s an example of the output I get from a Live CD I built using Bart’s PE Builder.

Live CD Feedback over SOL.jpg

Last Reviewed: 9/26/2012