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Título
iPXE Boot Process Detailed -
Descrição
The iPXE boot process described in this document, for conceptual knowledge or troubleshooting scenarios. -
Resolução
iPXE starts when the Network Card is selected as the boot option for a Device or Virtual Machine.
The PXE-enabled NIC of the client sends out a broadcast request to DHCP server, which returns with the IP address of the client along with the address of the TFTP server, and the location of boot files on the TFTP server.
NOTE: IP helpers may also help, when the SDA is on a distant network.The following steps describe how it works:1. Target Machine (either bare metal or with boot sector removed) boots from NIC.
2. The Network Interface Card (NIC) of the machine triggers a DHCP request.
3. The DHCP server intercepts the request and responds with standard information (IP, subnet mask, gateway, DNS etc.). In addition, it provides information about the location of a TFTP server and boot image (iPXE\KACE-SDA), this will be printed by the Device on screen, confirming the information obtained from the DHCP.
4. When the client receives this information, it reads the iPXE binaries and proceeds to contact the TFTP server (KACE-SDA) to get the boot image. (As soon as this happens, the TFTP Log in the KACE SDA, will print information about the Client Device IP Address and the bootfile that was requested, ipxe.efi for UEFI or undionly.kpxe for LEGACY BIOS).
Additional Note: Step number 4, is the first step where the KACE SDA is actually involved in the iPXE sequence, up until know, it was 'conversation' between the BIOS, the Network Card and the DHCP in charge of PXE Boot requests in this network.
5. The client downloads all the files it needs (kernel and root file system), and then loads them, a Welcome to K2000 followed by the TFTP server IP address obtained from the DHCP is printed on screen. (This IP needs to belong to the KACE SDA or KACE RSA).
6. The TFTP server (in our case, it's a KACE SDA or RSA) sends the boot image (KBEs), and the client executes it.(Manual Boots requires User interaction to select a KBE from the List).
7. The Boot Image is pushed over the network and it starts to load. (WindowsPE).
NOTE: The device must be transported into the SDA's TFTP Server, via DHCP, during the iPXE boot sequence, the KACE SDA will never reach\contact a device, they come into the SDA, helped by the DHCP or IP helpers.
(Configuring DHCPs or IP Helpers are considered Best Effort, and not part of the scope of support, for implementation, training, or custom setups services please contact Professional Services )