Cannot PXE boot on new fog server

  • I recently setup a new installation of Fog on an Ubuntu server VM (64-bit) on our VMWare esxi host (5.5). I have it installed and told it to not use the DHCP service through Fog as we have a Windows DHCP server. In the DHCP server I have option 66 set to the ip of the server and option 67 set to undionly.kpxe. However, when I boot to the NIC it spins on DHCP for several minutes before giving up and booting to the hdd. Does anyone have any ideas where my issue might be? If you need logs or additional info please let me know and I will do my best.

  • Moderator

    @jveronese the combination of subnet mask and IP address will say they are on the same subnet.

    i.e. with a subnet mask of would say they are on the same subnet.

    OK if they are on the same subnet, we can use fog to see if we can detect what is going wrong with dhcp.

    Follow these instructions and then upload the pcap to a google drive. We’ll take a look at the capture and see what is going on with dhcp

  • That’s the ip scope allowed for that network? (only if it’s private please)

  • @tom-elliott Ok, we have a subnet mask. How can I make sure these devices are on the same subnet then?

  • Let’s say you did the method of, while another machine was on with the same subnet mask. They would not be able to communicate because they’re on completely different networks.

  • @jveronese Subnet masks can be the same, but only describe where on a network a device will be able to reach.

    For example:

    192.168.1.x typically has as subnet mask. This makes the machine on this subnet (known as the 192.168.1 portion) only accessable to machines in the range of

    You can, however, have a subnet mask of on ANY network you’re trying to build. Let’s say you are working a network. The subnet mask of would only allow the devices to reach: - 255.

    A subnet mask of would allow you to connect to 10.0.0-255.0-255

    A subnet mask of would allow you to connect to 10.0-255.0-255.0-255

    So the mask doesn’t really indicate anything.

  • @george1421 Yes, when the device boots into Windows DHCP gives it an address. Both subnet masks are the same, so does that mean they are on the same subnet then?

  • Moderator

    OK so when you attempt to pxe boot the computer, it sits and spins for a bit then boots the hard drive. When it boots via the hard drive, does it pickup a dhcp address?

    And based on the answer provided above, is the fog server and the pxe booting client on the same subnet?

  • I could be anywhere. First place I’d look is to verify that the dhcp server can actually issue an IP to the machine requesting it. Second place I’d look is to find out if a “dumb” switch between the main connection and the device connection helps fix the problem. If a dumb switch works, this would seem to indicate a Power Saving thing or Spanning Tree in use on your network.