USB Over IP: Bridging Physical Hardware to Virtual Machines

The virtualization dream hits a wall when you need to plug something in. Keyboards, security tokens, license dongles, random number generators—the physical world intrudes on your perfectly abstracted infrastructure. Andrew from apalrd's adventures spent 19 minutes working through this friction with Digi's AnywhereUSB Plus, an eight-port USB-over-IP hub that costs $1,800 and promises to solve a problem most people don't know they have until they're already in too deep.

The Problem Space

Andrew's quest to "virtualize all the things" isn't unusual in certain corners of infrastructure management. Move everything to VMs, gain snapshot capability, improve disaster recovery, eliminate physical machines scattered across offices. Standard modernization playbook. But then you need to authenticate with a YubiKey. Or interface with test equipment that only speaks USB. Or access a hardware security module that absolutely cannot be emulated.

The AnywhereUSB Plus sits on your network—Andrew used 10 gig SFP+ fiber, though it'll fall back to gigabit Ethernet—and presents eight USB 3.0 ports to whatever clients authenticate. Those clients can be desktop VMs, headless servers, or the hypervisor itself. The device supports IPv6, VLAN tagging, VPN tunneling, and the usual enterprise authentication schemes (LDAP, RADIUS, TACACS+). It has FIPS compliance checkboxes. This is not hobbyist gear.

Three Deployment Patterns

Andrew tested three different architectures, each revealing different technical constraints and operational trade-offs.

First: GUI-based Ubuntu VM. The straightforward case. Install Digi's manager software (they provide DEBs for Debian-based systems and RPMs for Red Hat-based), authorize the client through the web interface, assign USB port groups, and connect. A flash drive appeared immediately. A webcam worked, though the latency chain was absurd—USB 3 to the AnywhereUSB, over 10Gbit fiber to a VM running OBS, viewed over an emulated VGA card on a laptop over Wi-Fi. "Not the most responsive," Andrew noted, which feels generous.

The bandwidth math is worth understanding. USB 3.0 can theoretically push 5 Gbps per port in each direction. Eight ports means 40 Gbps of potential bandwidth running through a 10 Gbps network connection—a 4:1 oversubscription ratio. Most USB devices don't saturate their theoretical maximum, but if you're planning to use multiple webcams or high-speed storage simultaneously, you'll hit that ceiling hard.

Second deployment: headless VM over SSH. This is where it gets interesting because this is where most people would actually use this device. Security tokens, license dongles, hardware that needs to persist across VM migrations—these don't need GUIs.

Andrew hit an immediate problem: the cloud kernel. Debian and Ubuntu ship stripped-down cloud kernels for VMs that remove "unnecessary" hardware support modules. The AnywhereUSB software requires a kernel module (already part of mainline Linux) designed for userspace USB emulation. Cloud kernels don't include it. The fix: switch to the standard kernel, reboot, and the service starts cleanly.

This reveals something about Digi's target market. They're not optimizing for cloud-native deployments. They're targeting traditional enterprise infrastructure being slowly migrated to virtualization—environments where someone might still be running Windows XP in a VM to interface with decade-old test equipment.

Third pattern: installation on the hypervisor itself. Andrew runs Proxmox, which is Debian-based and allows installing software directly on the hypervisor. This creates different operational dynamics. When a VM migrates between cluster nodes, it needs to maintain USB connectivity. If the VM handles the AnywhereUSB connection itself, that's network routing. If the hypervisor manages it, you need to think about device persistence and failover.

Proxmox lets you pass through USB devices by port number or by device ID. Andrew discovered that the device ID follows the physical hardware even when you move it between AnywhereUSB ports—useful for ensuring a specific YubiKey always appears as the same USB device to the VM, regardless of which physical port it occupies.

The Enterprise Price Point

Andrew addresses the price directly: "This guy is building itself as an enterprise product and it has an enterprise price to match." $1,800 for eight USB ports feels absurd until you map out the alternative. Custom USB-over-fiber solutions. Multiple single-port adapters that don't share authentication or management. Physical USB hubs at every hypervisor node. Someone's time configuring all of this versus centralized management through a web UI.

The feature set supports the pricing. VPN tunneling means you can deploy this in a remote facility and have it dial home. FIPS compliance matters in government and finance. Multiple authentication backends mean it integrates with existing identity infrastructure. IPv6 support that actually works is rarer than it should be.

Andrew notes: "I do wish I could find a cheaper version that's less enterprise-centric and enterprise priced, but this is what I got for you guys today." That cheaper version probably doesn't exist because the market is narrow and the support expectations are high.

The Use Cases That Actually Make Sense

Andrew's background in "shadow IT" (his term—"doing networking or information type work behind IT's back") gives him perspective on where this device solves real problems. He worked in test methods, building racks of equipment to stimulate and measure hundreds of wires on electronics under test. "We would be pulling in all kinds of different weird Ethernet, ISA, PCI, USB devices from around the world to emulate all of these signals we're trying to talk."

That was ten years ago and already outdated. Today, virtualizing that entire stack would provide snapshot capability, proper backup and disaster recovery, and eliminate the "PC running Windows XP running old software in the closet" problem. But it requires bridging to physical test equipment, some of which communicates over USB.

This is operational technology territory. Long hardware lifespans. Interfaces popular 15 years ago. Software that can't be updated. Equipment that costs six figures and needs to interface with infrastructure that didn't exist when it was manufactured. The AnywhereUSB Plus is solving a migration problem, not a greenfield deployment problem.

What Andrew Didn't Test

The video doesn't explore failure scenarios. What happens when the AnywhereUSB loses network connectivity? Does it buffer? Drop connections? How does a VM behave when its USB device suddenly disappears mid-operation?

Andrew also didn't dig into the security model beyond authentication. If this device is presenting USB ports over the network, what prevents USB-based attacks from traversing that network? The web interface uses HTTPS with a self-signed certificate by default—standard for enterprise gear, but worth noting.

The sponsored nature of the video (Digi provided the hardware) means certain questions don't get asked. Reliability over months of continuous operation. Firmware update process and frequency. Technical support responsiveness. Failure modes and warranty terms. These matter in enterprise deployments but don't surface in a 19-minute walkthrough.

The Labor Economics of Niche Hardware

Andrew's Linux-first testing revealed an interesting detail: "They're not using any proprietary kernel modules on Linux." This matters. Proprietary kernel modules create maintenance burdens—they break with kernel updates, require vendor support, lock you into specific kernel versions. Using existing Linux infrastructure (the userspace USB emulation module) means this device can work with future kernels without Digi's intervention.

That's a sustainability decision that reveals how Digi thinks about their support burden. They're not trying to build a moat through custom kernel code. They're leveraging existing Linux infrastructure and focusing their engineering on the network layer and management interface.

For the open source community, this approach has downstream effects. When enterprise vendors use mainline kernel modules instead of maintaining out-of-tree code, they're more likely to contribute fixes upstream when they find bugs. They're reducing the fragmentation of Linux USB support. It's a small signal, but it suggests a company that understands Linux deployment realities.

The device fills a genuine gap in virtualization infrastructure, priced for enterprises with specific migration challenges and legacy hardware dependencies. Whether that gap is wide enough to justify building a product—and whether $1,800 for eight USB ports makes sense for your deployment—depends entirely on what you're trying to virtualize and why you can't just leave it on physical hardware.

Dev Kapoor covers open source software and developer communities for Buzzrag.