In this article, you will learn everything you need to know about deploying operating systems using HEIMDAL's Network OS Deployment (PXE). Preboot Execution Environment is a cornerstone of modern IT administration for deploying and re-imaging computers. Instead of manually installing an OS on each machine using a USB drive or DVD, an administrator can boot many computers simultaneously over the network and have them automatically install a standardized OS image. This is a common practice in computer labs, data centers, and corporate environments.
1. Description
2. How does Network OS Deployment (PXE) work?
2. Network OS Deployment settings and repository
3. Configuring an OS Deployment Server
4. How does deployment work?
DESCRIPTION
This enables HEIMDAL Dashboard administrators to deploy Windows operating systems within their network effortlessly, using some of the following key functionalities:
- Repository Management: Easily manage your OS image repository through Network Settings.
- Image Management: upload and manage images of different Windows operating system instances.
- PXE Server Promotion: promote and manage a hostname to function as a PXE server.
- Inheritance Feature: Inherit repository settings from your reseller.
HOW DOES NETWORK OS DEPLOYMENT (PXE) WORK?
Network OS Deployment leverages PXE, a client-server protocol that allows computers to boot and install an operating system (OS) from a network rather than from a local drive or USB stick. The HEIMDAL Dashboard administrator can configure any device in the Device Info tab to act as an OS Deployment Server that serves an ISO image to any device on the network that requests a PXE broadcast. On the device that is promoted to OS Deployment Server, the HEIMDAL Agent will create 2 new services called Heimdal OsDeployment and Heimdal OsDeployment Checker that will be responsible for handling the ISO image download, the WindowsPE deployment, and the HTTP server broadcast.
NETWORK OS DEPLOYMENT settings and repository
To use Network OS Deployment, you need to have the Infinity Management licensing option enabled. To set it up, simply enable it within the Network Settings -> Network OS Deployment tab.
Network OS Deployment - turn ON/OFF the Network OS Deployment module.
Inherit Reseller Repository - allows you to inherit and use the ISO images found in the reseller repository. When enabled, corporate customers gain access to all ISO files uploaded by the reseller (source: Inherited) as well as those they upload themselves (source: Owner). However, they can only edit and delete the OS images that they have uploaded themselves. Corporate customers will find this option greyed out unless their reseller has enabled the Repository Distribution functionality from their Network Settings.
OS Image Repository - allows you to upload one or multiple ISO images to your repository. The ability to use the Network OS Deployment feature is strictly tied to having a repository of optical disc images of OS instances. After pressing the Upload OS Image button, a modal window is displayed, and you will be allowed to select an ISO file from your device, import/upload it, and add a description (friendly name).
Once the upload button is pressed, the selected .iso file starts uploading to the cloud. It's important to keep the browser page open until the upload is finished; otherwise, the upload will be stopped. The upload time is limited to 2 hours. If the upload takes more than 2 hours, the user will be logged out due to inactivity. 
IMPORTANT
If you are a reseller/MSP, you can also upload one or multiple ISO files to the reseller-tenant repository to be able to distribute them across corporate customers, thus saving time from manually uploading to each corporate customer. The reseller repository is available when logging in with your reseller HEIMDAL Dashboard user account in the Network Settings -> Network OS Deployment section. After enabling Network OS Deployment and uploading an ISO file, you can enable Repository Distribution to allow corporate customers to inherit and use the ISO file found in the reseller repository.
CONFIGURING AN OS DEPLOYMENT SERVER
As soon as you build your OS Images Repository, you can, from the Unified Endpoint Management -> Device Info -> Standard View, you can select one device and designate it as an OS Deployment Server by choosing the Add OS Deployment Server action (for an already-assigned OS Deployment Server, you get the options to Config OS Deployment Server or Remove OS Deployment Server). After clicking Add OS Deployment Server or when editing a previously selected PXE server, a modal window will appear. In this window, you can configure the OS Deployment Server.Check time interval [min] - allows you to set the interval at which |the HEIDAL Agent checks for new changes.
Enforce user authentication - allows you to set and use credentials (username and password) to get access to the OS image repository on the client device.
Download Path - allows you to set the default location to use when downloading ISO files. Make sure that the drive of the selected path has enough free space to accommodate the number of ISO files that are set to be downloaded.
By pressing the Add OS Image button, the user can select from the available ISO images sitting on the OS image repository. All the available ISO images are displayed in a grid (there are also options to edit and delete already downloaded ISO images).
Network Adapter - allows you to select the specific Network Interface Card (NIC) through which the Network OS Deployment (PXE) traffic will be routed. Select Automatic or choose a specific interface (e.g., Ethernet) from the drop-down menu.
Note: With the ability to select the desired Network Interface Card, PXE broadcasts can be limited only to machines located in the same subnet as the chosen adapter, ensuring precise control over deployment traffic. This provides greater flexibility, improves ease of use by simplifying targeting logic, and strengthens security by preventing unnecessary PXE exposure across unrelated network segments.
While an ISO image is being downloaded on the Network OS Deployment Server, its status is shown as Downloading. Once the download is complete, the status is updated to Completed, supplementing the “old” generic Pending status, which is now displayed when a new ISO image is added to the Available OS Images grid.
Post hitting the Confirm button and syncing the GP (Sync GP button in the HEIMDAL Agent), on the end users’ endpoints, two new services will be created and started: Heimdal OsDeployment and Heimdal OsDeployment Checker.
IMPORTANT
The Network OS Deployment functionality starts and works when all ISO files are downloaded from the repository. This means that if the HEIMDAL Agent is still downloading an ISO file, Network OS Deployment will not work yet. To see if an ISO file is fully downloaded, check the ISO image status on the OS Deployment Server.
A device designated as an OS Deployment Server will continue to work as an OS Deployment Server, no matter if a hostname changes (unless the Remove OS Deployment Server command is applied to the endpoint) takes place.
HOW DOES DEPLOYMENT WORK?
The PXE process relies on a combination of protocols, primarily DHCP (Dynamic Host Configuration Protocol) and TFTP (Trivial File Transfer Protocol), to transfer a bootable image from a server to a client. To connect endpoints to the OS Deployment Server, make sure boot priority is set to network, and follow the steps below:
- Client initiates PXE boot: When a client machine is turned on and configured to boot from the network, its network interface card (NIC) firmware takes over. It sends a DHCPDISCOVER broadcast packet on the network, but with a special PXE-specific request.
- DHCP server responds: The DHCP server on the network receives the request and provides the client with an IP address and other network settings. Crucially, it also includes information about the OS Deployment Server, such as the IP address of the TFTP server and the name of the boot file (often called the Network Bootstrap Program or NBP).
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Client downloads the boot file: Using the information from the DHCP response, the client uses TFTP to connect to the boot server and download the NBP. TFTP is a simple file transfer protocol that's easy to implement in the client's NIC firmware, making it ideal for this initial stage.
A Heimdal Agent notification pop-up is displayed at the start of the image download process, informing end users that boot resources are being downloaded and that temporary increases in network usage may occur. - Client executes boot file: Once the NBP is downloaded into the client's RAM, the client's firmware hands over control to it. This boot file is a small program with a boot menu (Windows PE).
- Authentication: on the client side, enter the username and password if asked.
- Loading WinPE: When loading Windows PE (WinPE), the system will load the Windows Preinstallation Environment.
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Select OS Image: choose the OS you want to install.
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Start the Windows setup: Proceed with the Windows setup steps.