Client tries to pull bootfile from DHCP server

[Base2Nathan]

I am having trouble with my fog setup. Fog is running on Ubuntu 18.04. DHCP server is Ubuntu 18.04 as well. When I try to boot a physical laptop into the fog server to network boot the machine tries to pull the undionly.kpxe file from the DHCP server. It never reaches out to the FOG server. I have successfully booted a VM into my fog server and uploaded a Linux Mint image but physical laptops fail. I have attached a photo of my /etc/dhcp/dhcpd.conf file. I also attached wireshark captures of the DHCP offer showing option 66 and a wireshark capture of my client trying to pull the bootfile from the DHCP server. Any help would be appreciated.
192.168.20.44 = DHCP
192.168.20.51 = FOG

[Sebastian Roth]

@Base2Nathan I think it should be option tftp-server-address (reference). Don’t set routers twice.

[Base2Nathan]

Hey @Sebastian-Roth. I made the change to option tftp-server-address and restarted isc-dhcp-server.service and it failed to restart. Any other guidance?

[george1421]

@Base2Nathan To take this in a slightly different direction.

If you would have picked the FOG server to be your dhcp server (not saying that you should have) it would have installed this config file for its isc-dhcp server: https://wiki.fogproject.org/wiki/index.php/BIOS_and_UEFI_Co-Existence#Example_1

This config file is designed to support both bios and uefi systems pxe booting. I should be possible to merge your config settings into this config file to install on your isc-dhcp server.

[Base2Nathan]

@george1421 So I figured it out. I took out the option tftp-server-name and placed next-server at the bottom of that section of the config file. Boots up fine now and installed a Mint image in a few minutes. Thanks for the help.

Also this is the link that helped me solve the issue. http://wiki.r1soft.com/display/CDP3/Configuring+DHCP+Server+on+Linux+(ISC+DHCPD)

[Sebastian Roth]

@Base2Nathan Good to hear you figured it out. You might wonder why the config George suggested doesn’t use option tftp-server-... and option bootfile-name at all. There are two places in DHCP packets where PXE boot information can be placed. One is DHCP options as you have used them. But there is also next-server and filename what are fields within the DHCP header information. Take a closer look at the wireshark dump…