How Does PXE Boot Work? Everything IT Admins Should Know

Anyone who’s deployed operating systems across dozens of machines—whether for a new lab, recovery scenario, or endpoint rollout—has probably encountered PXE boot. It’s not a flashy tool, but it’s reliable, efficient, and deeply woven into modern provisioning workflows.

Below, we break down how PXE boot works, when to use it, and what to keep in mind if you’re planning to rely on it for deployments at scale.

Understanding PXE and its working

PXE, or Preboot Execution Environment, enables a machine to start booting over the network—without needing a local drive or OS. That’s particularly useful when the device is fresh out of the box, or when internal storage has failed.

It works by coordinating a few key protocols:

• DHCP, which provides an IP address and boot file info.
• TFTP, used to pull the actual boot file.

PXE is built into most network interface cards (NICs) and functions with both BIOS and UEFI firmware, making it compatible with old and new systems alike.

What Happens During PXE Boot?

Here’s the general flow, though your setup might differ slightly depending on the environment:

1. System Startup: The firmware checks the boot order. If PXE is listed, the system hands control over to the NIC.
2. DHCP Discovery: A request is broadcast, asking not just for an IP, but also for boot file instructions. These typically include:

• A TFTP server address
• The name of the Network Bootstrap Program (NBP)

1. Downloading the Boot File: Using TFTP, the machine downloads the specified file. That might be a minimal loader, a PE environment, or even a pre-configured script for imaging.
2. Launching Deployment: Once the NBP is in memory, the system executes it. From there, you can start an OS install, trigger a script, or connect to a management console.

Why does PXE still matter?

Despite being decades old, PXE hasn’t lost relevance. It shines in use cases where:

• Physical access is limited or impossible.
• Uniform configurations are needed across multiple systems.
• Fast, repeatable deployments matter.

And here’s a lesser-mentioned point: PXE boot doesn’t just reduce manual steps. It also lowers the chances of user error, especially when imaging is standardized.

Where can you find PXE still being used?

You’ll find PXE workflows in:

• University computer labs resetting daily.
• VDI deployments where diskless systems are the norm.
• Bare-metal rollouts for new office hardware.
• Recovery workflows after a storage failure.

It’s often one part of a larger provisioning chain, not the end solution on its own.

How to secure PXE?

PXE, in its default form, assumes a trusted environment—which isn’t always the case. If left exposed, attackers can:

• Serve unauthorized boot images.
• Spoof DHCP responses.
• Intercept traffic during TFTP transfers.

To lock things down:

• Isolate PXE traffic in its own VLAN.
• Use UEFI Secure Boot whenever possible.
• Apply MAC filtering or ACLs at the DHCP server level.

It won’t solve everything, but it does tighten the gate considerably.

Troubleshooting PXE Boot Issues

PXE boot doesn’t always work the first time—and the issues are rarely obvious. If you’re stuck, some common causes include:

• DHCP options not set (Options 66 and 67 are the usual culprits).
• The TFTP server isn’t reachable or is misconfigured.
• You’re using a BIOS-based image on a UEFI device (or vice versa)..
• Firewall or VLAN rules are blocking broadcast traffic.

PXE and the Modern Stack

PXE might feel like old tech, but it fits right into today’s deployment ecosystems. It works with:

• Microsoft Deployment Toolkit (MDT)
• SCCM
• Linux-based imaging tools

And with support for HTTP boot in newer firmware, PXE is evolving—faster transfers, fewer issues, and better compatibility with modern infrastructure.

PXE booting simplified with ManageEngine

If you’d rather skip setting up DHCP scopes, TFTP servers, and troubleshooting boot image paths, tools like ManageEngine OS Deployer can simplify the whole process.

It gives you:

• An interface to manage deployment workflows.
• Support for BIOS and UEFI machines.
• Driver management and hardware-agnostic imaging.
• The ability to launch installations remotely.