BootfileName

BootfileName refers to the boot image filename used in network boot processes to fetch the initial loader from a TFTP server. It is typically supplied by a DHCP or BOOTP server as part of the boot information the client receives during startup.

In DHCP-based network booting, the server provides two key pieces of information: the boot server address (option 66, often called the next-server) and the boot file name (option 67). The client uses the boot server address to contact the TFTP server and then downloads the specified boot file name. In PXE environments, this boot file is usually a small boot loader such as pxelinux.0 for BIOS-based systems or a UEFI-compatible file like ipxe.efi.

BootfileName can be a simple filename or a path relative to the TFTP root. In more complex deployments, it may reference a script or a chain-loading mechanism that selects a subsequent image, such as an operating system installer or a virtualization host image.

Different boot methods require different files: BIOS-based PXE commonly uses a Linux-based chain loader like pxelinux.0; UEFI-based PXE often uses bootx64.efi or ipxe.efi; iPXE can use various scripts or kpxe variants. Administrators configure the appropriate boot file name per subnet, client class, or hardware type within their DHCP server to accommodate diverse boot scenarios.

Security and reliability considerations include ensuring the boot file comes from a trusted source, securing or restricting TFTP access, and monitoring for image integrity. Misconfigurations or unavailable boot files can prevent clients from booting, making careful administration of BootfileName essential.