Building a Home Network Router with Lenovo ThinkCentre
This blog post was automatically generated (and translated). It is based on the following original, which I selected for publication on this blog:
A pretty great Homelab firewall in a tiny package – The Lenovo M720q with SFP+ for OPNsense – YouTube.
Building a Home Network Router with Lenovo ThinkCentre
The Lenovo ThinkCentre M720q presents an interesting option for those looking to build a capable home network router. Combining a compact form factor with sufficient processing power and expandability, it can serve as a robust foundation for a network appliance. Let's delve into the hardware and software aspects of such a setup.
Hardware Overview
The M720q model typically includes an Intel Core i5 8400T CPU, up to 64GB of RAM, and a combination of NVMe and SATA storage options. The unit is equipped with a gigabit Ethernet port, but the real magic happens with the addition of a dual SFP+ PCIe card. This upgrade enables 10 Gigabit Ethernet connectivity, significantly boosting network speeds.
To accommodate the SFP+ card, a custom 3D-printed bracket is often used. This allows for the installation of the card in the compact chassis. The bracket typically includes a fan to ensure adequate cooling. The PCIe card is connected to the motherboard through a 90-degree riser.
Connectivity options on the M720q include DisplayPort, HDMI, USB 3.0 ports, and the standard Gigabit Ethernet port. This variety allows for flexible integration into existing network setups.
Software Configuration
To fully utilize the hardware, a virtualization platform like Proxmox can be installed as the base operating system. Proxmox allows for the creation of virtual machines (VMs), one of which can run a firewall/router distribution like OpenSense.
The key to this setup is PCIe passthrough. This technology allows the virtual machine to directly access the SFP+ network interface cards (NICs), bypassing the host operating system. As a result, OpenSense can manage network traffic at near-native speeds.
The integrated Gigabit Ethernet port on the motherboard is typically used for Proxmox's management interface, while the two SFP+ ports are assigned to the OpenSense VM, one for the WAN (Wide Area Network) connection to the internet and the other for the LAN (Local Area Network) connection to the internal network.
Within the OpenSense VM, one NIC is configured to obtain a DHCP IP address from the ISP (Internet Service Provider), while the other acts as the DHCP server for the local network. This setup mirrors a traditional router configuration.
Performance and Resource Usage
When properly configured, the M720q-based router can deliver impressive performance. With PCIe passthrough, the OpenSense VM can handle gigabit and even multi-gigabit internet connections with minimal CPU overhead. This leaves ample resources for other tasks, such as running Pi-hole for DNS ad-blocking, Caddy for reverse proxying, Tailscale for secure remote access, and Home Assistant for smart home automation.
Despite running multiple services, the system's power consumption remains relatively low. A typical configuration might draw around 25-38 watts, making it an energy-efficient solution for a home network.
Further Considerations
While the M720q offers a compelling solution, it's worth noting that certain models may have limitations in terms of PCIe lanes for M.2 slots. For those seeking more storage expandability, the Lenovo ThinkCentre M920X or P330, which feature two M.2 slots, might be preferable.
One could ask the question whether the slightly higher cost of an M920X or P330 is justified by the increased storage capabilities. This will depend on the specific needs of the user.
Ultimately, building a home network router with a Lenovo ThinkCentre M720q offers a balance of performance, flexibility, and energy efficiency. It provides a solid foundation for a modern, high-speed home network.