Laptops not PXE booting on clean install of v1.6.0-RC-14

[DBailey635]

Hi, Hope you can help me with this.

I was having a dreadful time upgrading from v1.5 to v1.6 (database wouldn’t upgrade and had become corrupt), so I decided to export everything I could, wipe the server, and begin from scratch (the “nuke it from orbit” approach).

I installed a fresh copy of Ubuntu Server 26.04 and then downloaded and installed FOG v1.6.0-RC-14 using the link to the .tz file on the website (not via git). After it installed and after importing all my data again (groups, images, hosts) and setting the new Bootfile Name to “secureboot/snponly-shimx64.efi” on my MikroTik router’s DHCP server, I went to try and boot one of my classroom Dell laptops. It wouldn’t boot from iPXE. I got the following on screen (from a screen cap):

>>Start PXE over IPv4.
  Station IP address is 192.168.5.119

  Server IP address is 192.168.5.25
  NBP filename is secureboot/snponly-shimx64.efi
  NBP filesize is 1048424 Bytes
Downloading NBP file...

  NPB file downloaded sucessfully.
Fetching Netboot Image secureboot/snponly.efi
iPXE initialising devices...
autoexec.ipxe... ok

iPXE 2.0.0 (g12798) -- Open Source Network Boot Firmware -- https://ipxe.org
Features: DNS HTTP HTTPS iSCSI TFTP VLAN AoE EFI Menu
Checking net0 for DHCP...
Configuring (net0 08:92:04:29:13:b6)........ ok
Received DHCP answer on interface net0
Trying proxy DHCP...
Checking for next-server...
Starting netboot to default.ipxe...
tftp://192.168.5.6/default.ipxe.................. Connection times out (https://ipxe.org/)
Chainloading failed. hit 's' for the iPXE shell; reboot in 10 seconds

My server is 192.168.5.25
My MikroTik router with DHCP is at 192.168.5.1
IP 192.168.5.6 is another MikroTik router working in bridged mode as a switch that isn’t serving DHCP at all.

I’ve checked the TFTP service is running and active on my Ubuntu server. Files in the TFTP folder are set so that everyone can read them (777). Firewall is disabled. The only thing I changed on the MiroTik was the Bootfile Name. Everything worked fine in earlier FOG version, so I’m not sure why it won’t boot now that I’m running 1.6.

Please can you make any suggestions?

PS: I know a bit about Linux, but am not an expert or a full-time sysadmin. Am happy to dig into logs if you tell me which ones.

[Tom Elliott]

@DBailey635 Look at the address in the failure: iPXE asks 192.168.5.6 for default.ipxe. Your FOG server is 192.168.5.25. FOG does not supply that address. iPXE gets it from the DHCP answer it receives.

The first download (snponly-shimx64.efi) works, so the first DHCP offer is correct. iPXE then does its own DHCP request. A second DHCP server answers it and names .6 as the next-server. .6 has no TFTP server, so the request times out.

The usual cause is a MikroTik in “bridge mode” that still runs its default DHCP server on the bridge interface. Please check:

• On the MikroTik at .6: run /ip dhcp-server print and /ip dhcp-relay print. Disable any entry you find.
• On the MikroTik at .1: under /ip dhcp-server network, set next-server to 192.168.5.25.

To confirm, run tcpdump -ni any port 67 or port 68 on the FOG server while the laptop boots. You should see offers from two servers.

[DBailey635]

@Tom-Elliott

Thank you!

As you thought, it was a double DHCP server… Even though .6 was in bridge mode, the DHCP server on it was still enabled, unlike the other MikroTik switches we have. Disabling it brought the iPXE booting back. I’ve run a re-inventory task and am now running an image capture task.

I’ll have to keep a future eye open for that as we expand our classroom network.

Cheers!