A Raspberry Pi Zero makes a surprisingly good home lab subnet router

Every home lab eventually collides with the same wall: you want to reach your machines from outside, and your ISP won’t let you. Carrier-grade NAT — increasingly common on consumer and NBN connections — means there’s no public IPv4 address and no port forwarding, so the classic “expose a service on the router” playbook simply doesn’t exist. A writer at XDA Developers recently documented their solution, and it’s a lovely piece of lateral thinking: they gave the oldest, weakest board in the drawer — an original Raspberry Pi Zero — the most important job in the lab.

The ingredient that makes it work is a mesh VPN such as Tailscale. Instead of opening ports, every device you care about joins a private overlay network and talks to its peers over encrypted WireGuard tunnels, using UDP hole-punching to sneak through NAT. No inbound ports, no cloud server rental, and the free tier is generous enough for home and small-office use. It’s the answer to CGNAT that doesn’t involve calling your ISP or paying for a static IP you can’t get.

The clever part is how little of it you actually need to install. Installing the VPN client on every server, VM and container gets old fast — especially if you rebuild nodes regularly for experiments. The fix is a subnet router: one device joins the mesh and advertises your local subnet as a route. From that moment, anything connected to the VPN can reach everything on your LAN — servers, printers, smart gadgets, the lot — with no client installed anywhere else. One board, one configuration, whole-network coverage.

And that’s where the Pi Zero earns its keep. Routing packets between a VPN tunnel and your LAN is almost no work at all for a modern CPU, let alone a humble ARM11. The XDA author paired theirs with DietPi to strip the OS down to essentials, enabled IP forwarding, and enabled route advertisement with a single command:

tailscale set --advertise-routes=192.168.0.0/24

Approve the route once in the admin console and you’re done. That $15 board everyone wrote off is now the front door to your entire network.

A few practical notes before you raid the parts drawer:

  • Connect it wired if you can. The original Zero has no Ethernet port, and subnet routing over Wi-Fi is fine for SSH and dashboards but will bottleneck big file transfers. A USB Ethernet adapter helps; a Pi Zero 2 W (or any spare Pi) is better again if you have one.
  • Keep a fallback path. A subnet router is a single point of failure. If remote access matters to you, a second device advertising the same route elsewhere on the LAN gives you failover — or at least a way in when you unplug the wrong cable.
  • Lock the tailnet down. Turn on device approval, use Tailscale’s ACLs to limit which devices can reach which subnets, and consider an exit node so roaming laptops can keep lab access off public Wi-Fi.
  • Mind the power supply. A flaky USB charger will brown out a Pi under network load and you’ll spend an evening debugging a problem that costs $10 to fix.

For small businesses the same pattern applies with a straight face: secure remote access to an office LAN without opening a single inbound port, without a VPN concentrator appliance, and with the audit trail of who connected sitting in one admin console. Not bad for the board at the bottom of the drawer — and a good reminder that in networking, the boring jobs are often the important ones.

Cutting AI model costs with OpenAI-compatible API gateways

AI APIs have quietly become a line item for a lot of small businesses. A customer-service assistant here, a document summariser there, and suddenly the monthly bill is measured in hundreds of dollars — most of it spent on frontier models doing work a cheaper model could handle. The good news is that this is one of the few areas in tech where switching costs are close to zero, and a new wave of services has grown up around exactly that.

The pattern looks like this: instead of holding separate accounts with OpenAI, Anthropic, Google and the rest, you point your code at a single gateway that speaks the OpenAI API dialect — the de facto industry standard. Behind that one endpoint, the service routes your requests to whichever provider and model you ask for, at prices that are often well below list. One recently launched example, CheaperInference, promises access to leading models through one OpenAI-compatible API with savings of up to 60% on inference costs. It is new enough that there is little independent coverage yet, so treat it as an example of the category rather than an endorsement — but the category itself is well established.

Why does this work? Because the OpenAI API format became the lingua franca of the industry. Nearly every model provider and open-source framework speaks it, which means an aggregator only needs to translate at the edges. For you, that means the migration is a one-line change — swap the base URL and API key — and your existing code, SDKs and tooling keep working. That same property is your negotiating leverage: when a better price appears elsewhere, you can act on it in minutes, not weeks.

The real savings, though, come from pairing a gateway with some straightforward habits:

  • Route by task, not by default. Most workloads don’t need a frontier model. Classification, extraction, drafting and routing tasks run happily on smaller models that cost a tenth as much. Keep the expensive models for the genuinely hard requests.
  • Measure before and after. Run the same real-world prompts across two or three models and compare quality against cost. You will usually find one or two tasks where the premium model earns its price, and several where it does not.
  • Cache and batch. Identical requests don’t need to hit the API twice, and most providers offer half-price batch processing for work that isn’t time-critical.
  • Watch the context, not just the price. Long documents fed to a “cheap” model with a large context window can cost more than a smart model given a summary. Trim what you send.

There are caveats worth respecting. Your prompts and data pass through a third party, so check the privacy terms before sending anything sensitive — for regulated data, this may rule smaller aggregators out entirely. Latency can differ from going direct. And a very new service deserves a cautious rollout: start with internal, low-stakes workloads, keep an eye on uptime, and keep that one-line switch back to the direct provider ready.

For homelab tinkerers and small businesses alike, this is a rare win-win. The competitive market and the common API dialect mean the cost of experimentation is minutes of your time, and the payoff is a bill that scales with what your workload actually needs rather than what the default model charges. Services like CheaperInference are worth a look — the worst case is you learn where your money was going.

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