Saturday 26 April 2014

Start PXE Over IPv4

Question:

My six months old HP Laptop which was working fine all along, once did not boot and I could see the text "Start PXE over IPv4" in the black MS DOS like screen and was unresponsive to keyboard and mouse. I waited for some time and then used the power button to hard shut down and then powered it again. This time it booted normally without any issues. Though the problem did occur thereafter, I am curious to know what PXE is all about. Can you explain what it is and the reason for it showing up?

By: Anonymous

Answer:

PXE is the short form for Preboot Execution Environment.It allows PCs or laptops to boot over a network as against booting from the local hard disk. Those who have worked with Novell Netware should be familiar with this network booting, where the Network Interface Cards carry a small add on chip containing the Network Boot Program, which will perform the boot over the network.

To address the large deployment challenges, Microsoft began developing the technology that would allow for network-based installation and PXE was the solution for this. To PXE boot a PC, the BIOS should be setup to boot from network. When set so, the BIOS will first get an IP address for the PC from the PXE Server and thereafter to get the boot image using TFTP on to the RAM and then boot out of that image.

Now in your case, as you have described the issue, it just happened, without you changing any BIOS setting. Normally the BIOS have multiple boot options configured with an order of priority. Your BIOS probably had the Network boot as one of the boot options and on that occasion, for some reason, your hard drive would have been unresponsive for a moment at the time of boot, as the next choice, the BIOS would have attempted to boot from network using PXE. As it might not find a PXE server over the IPv4 network it stayed there. 

You can check the BIOS by pressing F2 when your laptop boots and check if the network boot is configured as an option. You may disable this option, if you are not using the Network booting in your environment. On a different note, you may want to check why your local hard disk was not responsive for the boot on that occasion. That could be an odd occurrence and  the disk may be just fine too.

To know more about PXE booting, check the following resources: