PXE

PXE stands for Preboot Execution Environment, a standard that enables network booting of client machines equipped with a PXE-capable network interface card. In a typical PXE deployment, a client boots from a small network bootstrap program provided by a PXE server rather than from a local disk. The environment is built around DHCP and TFTP and supports operating system installation, system maintenance, and diskless workstations.

During boot, the client broadcasts a DHCP Discover message including the vendor class option to indicate PXE capabilities. A DHCP server responds with an IP address, as well as the address of a TFTP server and the file name of the network bootstrap program (the NBP). The client then downloads the NBP via TFTP and executes it. The NBP may load a first-stage OS installer or chainload to another boot environment such as iPXE, which can use HTTP, HTTPS, or other protocols to retrieve the full OS image.

PXE variants include legacy BIOS-based PXE and UEFI PXE; some networks use iPXE for richer features and alternative transport protocols. Security considerations: TFTP is insecure, and deployments may mitigate risk with network segmentation, authenticated servers where supported, and careful boot image control. Limitations include dependence on the network, potential single points of failure, and bandwidth constraints.

PXE is widely used for mass OS deployment, diskless workstations, and remote maintenance. It integrates with imaging and provisioning systems to deploy Windows, Linux, and other operating systems, enabling centralized administration of large-scale environments.