Raspberry Pi 4 finds new role as network monitor in home lab

At a glance:

• The author migrated Home Assistant from a Raspberry Pi 4 to a mini PC and repurposed the Pi as a dedicated network‑monitoring node.
• Pi‑hole paired with Unbound now handles all DNS queries locally, eliminating third‑party DNS providers.
• Tailscale provides zero‑config remote access to the monitoring stack without port‑forwarding.

Why the switch from Home Assistant to a mini PC

The Raspberry Pi 4 had served as the hub for Home Assistant for over a year, even booting from an NVMe SSD. As the author added more ESPHome devices, the Pi’s 4 GB RAM ceiling became a bottleneck, prompting a move to a small form‑factor PC. Rather than discard the Pi, it was given a fresh purpose: a headless server that continuously watches the home network, whether the author is at home or away.

Setting up Pi‑hole and Unbound for local DNS resolution

With a minimal OS installed, the author deployed Pi‑hole on the Pi to block trackers and malicious domains for every device on the network. The initial setup took under 15 minutes, followed by a careful pruning of ad‑lists to keep only essential entries. To avoid reliance on public DNS resolvers like Cloudflare or Google, Unbound was added as a local recursive resolver. Unbound queries the root servers directly, meaning no external DNS provider ever sees the author’s queries. This configuration not only speeds up browsing on phones, tablets, smart TVs and computers, it also offloads DNS work from the router and mini PC, keeping those devices focused on their primary workloads.

Adding ntopng and NetAlertX for traffic visibility

The router only displayed a list of connected devices, offering no insight into bandwidth usage or background chatter. To fill that gap, the author installed ntopng on the Pi. Running passively, ntopng surfaces bandwidth‑hungry devices, active protocols and any anomalous traffic. It helped pinpoint midnight spikes that turned out to be routine device backups. The tool also exposed background telemetry, ad‑targeting requests and software update checks that would otherwise go unnoticed.

NetAlertX complements ntopng by watching for new devices joining the network and sending alerts when unfamiliar hardware appears, especially those that connect intermittently. Together, these utilities give a granular view of the home network that the router alone cannot provide.

Remote access with Tailscale simplifies monitoring from anywhere

To reach the monitoring stack while away, the author installed Tailscale on the Pi 4 instead of the mini PC. A two‑node Tailscale mesh (one node on the Pi, another on the mini PC) lets the author pull up NetAlertX, ntopng, Pi‑hole and Uptime Kuma dashboards from any location without opening ports, tweaking firewalls or chasing dynamic IPs. The mini PC also runs a Tailscale node to expose Proxmox VMs remotely. The entire setup was assembled in about 15 minutes and now provides reliable, low‑maintenance remote access.

Power draw and the Pi’s renewed purpose

Despite handling multiple services, the Raspberry Pi 4 draws only 3–5 watts, making it an energy‑efficient always‑on component. Its modest power consumption is a small price for round‑the‑clock DNS filtering, traffic analysis and health checks. By offloading these tasks from the mini PC, the Pi creates a clean separation of concerns: when something fails, it’s immediately clear which box needs attention. In short, the Pi 4 now “does less, but better,” earning a permanent spot in the author’s homelab.

Hardware specifications of the Raspberry Pi 4

• Storage: MicroSD card slot
• CPU: Arm Cortex‑A72 (quad‑core, 1.8 GHz)
• Memory: 1 GB, 2 GB, 4 GB, or 8 GB of LPDDR4
• Operating System: Raspberry Pi (Official)