In any enterprise homelab or MSP operations fleet, nothing kills operational momentum quite like hunting down an 8GB USB thumb drive, firing up Rufus or BalenaEtcher, and waiting five minutes to burn an ISO just to re-image a server or test a hypervisor build. If you need to image three machines across separate rooms or racks, you either juggle flash drives or burn an entire afternoon.
The classic alternative—traditional PXE with TFTP and WDS/Syslinux—comes with its own severe headache in modern environments: VLAN segmentation. In my network, administration workstations live on VLAN 10 (10.1.10.0/24), servers live on VLAN 20 (10.1.20.0/24), and management lives on VLAN 1 (10.1.1.0/24). Traditional PXE broadcasts (UDP ports 67 and 68) hit a hard wall at the router boundary. Here is how I deployed iVentoy v1.0.45 in ExternalNet mode paired with UniFi DHCP options to achieve zero-touch, cross-VLAN gigabit UEFI booting across my entire network.
1. Architecture: The Multi-VLAN Boot Flow
iVentoy completely upends the traditional PXE model by replacing fragile, snail-paced TFTP transfers with high-speed HTTP ISO streaming over TCP port 16000. Under ExternalNet (Mode 2), iVentoy acts strictly as the bootloader and HTTP server, deferring all IP address assignment to the central UniFi Dream Machine Pro gateway.
[ Client Laptop on VLAN 10 (10.1.10.175) ]
│
▼ 1. DHCP Discover (UDP 67)
[ UniFi UDM Pro Gateway (10.1.1.1) ]
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▼ 2. DHCP Offer: IP + Option 66 (10.1.20.10) + Option 67 (iventoy_loader_16000_uefi)
[ Client NIC Firmware ]
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▼ 3. TFTP Request: iventoy_loader_16000_uefi (UDP 69)
[ iVentoy Server on HV2 (10.1.20.10) ]
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▼ 4. Transmits lightweight iPXE Bootloader
[ Client Boots iPXE Engine ]
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▼ 5. High-Speed HTTP ISO Stream (TCP 16000)
[ Raw ISO from H:SharesData delivered over Gigabit LAN ]2. Server Deployment: Running iVentoy in Mode 2 on Hyper-V
The iVentoy core runs directly on my secondary Windows Server 2022 Hyper-V host, HV-HYPERV-02 (10.1.20.10). To guarantee high availability across host reboots, iVentoy is registered as an automated Windows service rather than run from an interactive desktop session.
# Verify iVentoy Service State on HV-HYPERV-02
Get-Service -Name "iVentoy" | Select-Object Name, Status, StartType, BinaryPathName
# Expected Output:
# Name Status StartType BinaryPathName
# ---- ------ --------- --------------
# iVentoy Running Automatic C:iVentoyiventoy-1.0.45iVentoy_64.exe -Service -RWithin the iVentoy web management console at http://10.1.20.10:26000, configure the DHCP configuration parameter to ExternalNet. This mode disables iVentoy’s internal DHCP daemon, preventing catastrophic rogue DHCP collisions on VLAN 20, and instructs the daemon to listen for cross-subnet boot requests.
3. Storage Fabric: Symlinking Multi-Terabyte ISO Shares
By default, iVentoy expects ISO files inside its local directory at C:iVentoyiventoy-1.0.45iso. However, keeping multi-gigabyte ISOs on the C: drive is poor sysadmin hygiene. My server hosts a dedicated 4TB volume mapped to H:SharesData (accessible over SMB as 10.1.20.10Data).
Using an NTFS directory junction, iVentoy’s ISO folder transparently reads from the large storage share:
# Create Directory Junction from iVentoy to Data Share
New-Item -ItemType Junction -Path "C:iVentoyiventoy-1.0.45iso" -Target "H:SharesData"
# Verify Directory Target
Get-Item "C:iVentoyiventoy-1.0.45iso" | Select-Object FullName, LinkType, TargetWhenever a new Windows 11 build, Ubuntu Server 24.04 LTS, TrueNAS SCALE, Proxmox VE, or Clonezilla ISO is downloaded on my administrative workstation, I drop the .iso straight into network share Y:SharesData. A single click of Refresh in the web console updates the PXE boot catalog immediately.
4. UniFi Gateway Integration: Configuring Options 66 & 67
The secret sauce to cross-VLAN network booting lies in the DHCP scope options of your core router. In the UniFi Network Controller (running on UDM Pro), navigate to Settings → Networks and edit NET-WORKSTATIONS-VLAN10 and NET-MGMT-VLAN1:
# UniFi Network DHCP Custom Options:
Network: NET-WORKSTATIONS-VLAN10 (10.1.10.0/24)
DHCP Boot: Enabled
Option 66 (Next-Server / Boot Server IP): 10.1.20.10
Option 67 (Boot Filename): iventoy_loader_16000_uefi
Network: NET-MGMT-VLAN1 (10.1.1.0/24)
DHCP Boot: Enabled
Option 66: 10.1.20.10
Option 67: iventoy_loader_16000_uefiWhen an unconfigured workstation or bare-metal server on VLAN 10 powers on with network boot selected in UEFI, the UDM Pro answers the initial DHCP broadcast, assigns an IP in the 10.1.10.0/24 pool, and hands the client the exact IP of the iVentoy server (10.1.20.10) along with the loader binary.
5. Firewall Scoping & High-Speed HTTP Streaming
Unlike old-school TFTP which transfers 512-byte blocks with lockstep ACKs (taking 15–20 minutes to boot a modern 6GB Windows installer), iVentoy only transfers a tiny 2MB iPXE bootloader over TFTP (UDP 69). Once the iPXE kernel initializes on the client, it establishes a native TCP HTTP stream on port 16000 directly to the host.
# Windows Advanced Firewall Rules Required on 10.1.20.10
New-NetFirewallRule -DisplayName "iVentoy-HTTP-Stream" -Direction Inbound -Protocol TCP -LocalPort 16000 -Action Allow
New-NetFirewallRule -DisplayName "iVentoy-TFTP-Boot" -Direction Inbound -Protocol UDP -LocalPort 69 -Action Allow
New-NetFirewallRule -DisplayName "iVentoy-Web-Mgmt" -Direction Inbound -Protocol TCP -LocalPort 26000 -Action Allow
New-NetFirewallRule -DisplayName "iVentoy-NBD" -Direction Inbound -Protocol TCP -LocalPort 10809 -Action AllowBecause the transfer utilizes standard TCP window scaling over full gigabit (and 10GbE inter-VLAN SFP+ trunks), a full Windows 11 installation media boots to the setup screen in under 14 seconds across VLAN boundaries.
6. Production Verification: The Bare-Metal Fleet Test
During our recent lab disaster recovery drill, we verified cross-VLAN network booting across three completely distinct physical architectures:
| Device Tested | Client VLAN & Subnet | Boot Mode | Measured Boot Time | Target OS |
|---|---|---|---|---|
Dell PowerEdge R710 |
VLAN 20 (10.1.20.0/24) | UEFI x64 | 12.4s | XCP-ng 8.3 Base Install |
Lenovo ThinkPad P-Series |
VLAN 10 (10.1.10.0/24) | UEFI SecureBoot | 9.8s | Windows 11 Enterprise 24H2 |
Intel NUC Edge Node |
VLAN 1 (10.1.1.0/24) | Legacy BIOS (x86) | 16.2s | Proxmox VE 8.2 |
Every system booted cleanly without touching a single USB thumb drive. In a high-tempo enterprise or MSP lab, deploying iVentoy in ExternalNet mode delivers the ultimate peace of mind: instant, repeatable bare-metal provisioning across any subnet in your network.