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Hi I am new to BIOS and UEFI firmware. I am using PXE to download boot images for UEFI and BIOS. I found that when I do network boot using BIOS, it broadcast UDP packets and my PXE server can process it. But with same configuration if I do network boot using UEFI, target system does not broadcast UDP packets.

I have created a target system (bare metal system) on VMware ESX 5.5.

I am using wireshark to debug. I can see that In case of EFI based boot target does not get the ip address. Even though my DHCP server broadcast DHCPOFFER packets, target continuously sends the DHCPDISCOVER packets. I mean at some point in time target has to send DHCPREQUEST packet. But same thing works fine if I boot through BIOS.
Above problem get solved If I add bootfile name and nextaddress in dhcp.conf (DHCP Server is in Linux). But as per my requirement I can not hard code the nextAddress and bootfile name, it will be added on fly in PXE server.

Edit 2: So in my case I am adding all the required parameters at PXE side like next server address, boot file name etc. But if I do that I am not getting reply (DHCPREQUEST) back from client (UEFI based client) . But if configure same parameter at DHCP server it works well.

In case of BIOS in same environment, I have configured all parameters in PXE server and I am getting reply back (DHCPREQUEST) from client.

Just a pointer do we need to enable something at UEFI client to listen PXE parameters (Options). In my case I have made "EFI NETWORK" as primary boot.

Please help me on this. Thanks.

Manoj Jain
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1 Answers1

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in both cases when the target starts a network boot it will initially broadcast the DHCP DISCOVERY packets. If you do not see them when net booting UEFI based targets then you are probably not really netbooting or you have some firewall issue.

Edit 1. You have a DHCP and a PXE server both providing booting info? that's not good. You can either have:

  1. DHCP server offering PXE parameters
  2. Regular DHCP server plus a proxyDHCP only offering PXE parameters. read what a proxy server does here

If efi fails to get the IP it is because is not receiving a an IP "plus" the PXE parameters.

Pat
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  • Thanks for reply. Sorry I am late to revert. Yes I can see the DHCPDISCOVER packets, I am using wireshark to debug. But I can see that Incase of EFI boot target does not get the ip. It continuously sends the – Manoj Jain Feb 10 '15 at 08:42
  • Thanks for reply Pat. Sorry I am late to revert. Yes I can see the DHCPDISCOVER packets. I have updated my question please have a look. – Manoj Jain Feb 10 '15 at 08:55
  • Thanks Pat. Yes I have configured all parameters in PXE server. Please see my comments in EDIT2. – Manoj Jain Feb 13 '15 at 10:29