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Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →The computer in the headline is a Raspberry Pi Zero 2 W, and the software is Pi-hole, a DNS sinkhole. Every device on your network asks a DNS server for the address behind each domain name before it can connect. Pi-hole sits at that step. When a device asks for a domain on a block list, Pi-hole can refuse to resolve it, so the request never reaches the outside server. The result is network-wide filtering of some ads and telemetry (usage-reporting) requests, including on devices such as Roku boxes and smart appliances that cannot run a browser extension. It also keeps a log of the domains each device asks for. It does not block every ad, and its logs are not a complete record of your traffic.
What the $20 computer is, and what it actually does
The “$20” in the headline comes from the original How-To Geek article, syndicated on Yahoo Tech and dated September 23, 2026. That article gives “about $15” for the Pi-hole setup in its body text, so the two figures already disagree. Treat both as the article’s framing at that date, not as a verified price. Hardware prices and stock change, so check current listings before buying.
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Pi-hole is free software that runs on a small, always-on machine. The article names three hosts: the Raspberry Pi Zero 2 W, which it presents as the compact choice; a Raspberry Pi 4 or an older PC, for readers who want more headroom; and a container on a Proxmox server, for readers who already run one.
How DNS filtering works in practice
The article’s core explanation is short: “A Pi-hole works as a DNS sinkhole.” In practice, the process looks like this:
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- A phone, laptop, TV, or appliance needs the address for a domain, such as an ad server or a telemetry endpoint.
- It sends that lookup to its configured DNS server. If that server is Pi-hole, the lookup arrives there first.
- If the domain is on an active block list, Pi-hole does not return the normal address, so the device never contacts that server.
- If the domain is not blocked, Pi-hole forwards the lookup upstream and returns the answer as usual.
Because the filtering happens during name resolution, it works without installing anything on each device. The trade-off is the mirror image of that convenience: a device that uses a different DNS server, including one hard-coded into an app or set by a VPN, is outside the filter.
What it blocks well, and what it cannot block
Network-level filtering is strongest against ad and tracking domains that are served from their own hostnames. It is weakest where the ad and the content share a domain. The article names YouTube and Twitch as examples, where ads can come through because they are delivered from the same place as the video. Do not expect Pi-hole to remove all streaming ads.
Devices that cannot run a browser blocker
The article’s most practical argument is for devices where browser extensions are unavailable. Roku streaming boxes and smart appliances such as a fridge with a screen are the examples it gives. If those devices use Pi-hole for DNS, their blocked domains are filtered at the network level. The benefit depends entirely on the device actually using Pi-hole.
Telemetry and app behavior
Some TVs have telemetry domains that other services depend on. The article warns that blocking them can stop some TV apps from opening, so the first sign of a problem may be an app that will not launch. Adding the affected domain to an allowlist is the usual fix.
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Query logs: visibility, not a full traffic capture
Pi-hole’s query log shows which domains each device asked for and whether each request was allowed or blocked. This is useful for spotting a device that is unusually chatty or asking for unfamiliar domains. It is not a packet capture. It does not show the content of traffic, traffic that bypasses DNS, or connections made directly to IP addresses. The article suggests that filtering noisy requests can make unusual DNS activity easier to notice, but it does not claim that Pi-hole alone prevents compromise or reliably identifies malware.
The article’s illustrations are also not measurements. It describes a household generating “hundreds” of requests and a 10,000-requests-across-20-devices example. Neither is a study or a measured population figure. Your own numbers will depend on how many devices you run and how they behave.
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- powful cputhe cpu of the raspberry pi 4 model b adopts the latest arm cortex-a72 architecture, which is also used in high-performance smartphones, and has evolved into a real pc.the operating clock has been changed from pi3's 1.2ghz to 1.5ghz, and the speed has become a different dimension with the updated architecture.
- video output/gputhe on-board gpu of the raspberry pi 4 supports 4kp@60 and newly supports h.265 decoding, opengl es 3.0, etc.as for the video output, two micro hdmis with smaller connectors are installed, and the raspberry pi 4 also supports dual screen output.
- usb 3.0with a new soc, the speed of the raspberry pi 4 around i/o has been improved, and finally usb 3.0 is supported.usb boot is faster and more convenient.
- network&bluetoothgigabit ethernet (wired lan) has also been significantly speeded up from 300mbps of pi 3b + to 1000mbps (logical value).in addition, bluetooth supported version has been upgraded to 5.0, and the transfer speed of pi 4 has been doubled.
- power input connectorthe power input connector of the raspberry pi 4 has been changed to usb type c. it is easier to use than micro usb and can supply a larger current reliably.the power requirement of raspberry pi 4 model b is 5v 3.0a, which is higher than the previous model.
Choosing a host: the three options compared
The article names the three hosts but gives no benchmarks or comparative prices. The table lists what the article states and marks everything else as not stated, so you can fill the gaps with figures you verify yourself.
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1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errors| Host | Role described in the article | Price | Power, size, and performance |
|---|---|---|---|
| Raspberry Pi Zero 2 W | Compact option; the headline computer | Not verified at publication; article text gives about $15 for the setup | Not stated in the article |
| Raspberry Pi 4 | Option for readers who want more headroom | Not stated in the article | Not stated in the article |
| Older PC | Option for readers who want more headroom | Not stated in the article | Not stated in the article |
Before choosing, check the factors that matter for your setup: current purchase cost and availability, physical footprint, power draw, whether the host connects by Ethernet or Wi-Fi, memory and storage, and how many clients and queries you expect. Ethernet is the more stable option for a DNS server that every device depends on. Do not assume that one host is faster or more reliable than another without measuring it yourself.
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Reliability: the single point of failure
The article is direct about the main risk: “your Pi-hole will be a single point of failure; if the Pi or the SD card dies, your DNS will fail, and you’ll lose access to the internet.” That is the most important trade-off in this setup. When the host stops answering DNS queries, devices that depend on it stop resolving names, even though the wider connection may still be up.
The article suggests two mitigations:
- A second Pi-hole instance. Running a backup on another host means a failed unit does not take down name resolution for the whole network, provided devices or the router can use both.
- Fallback DNS. A secondary DNS server lets devices keep working when Pi-hole is offline. The trade-off is that queries sent to the fallback are not filtered, so ads and telemetry return while the primary is down.
Keep a copy of your configuration and block-list settings, and plan for how you will restore them if the SD card fails. The article does not give a restore procedure, so use the Pi-hole documentation for your installed version.
False positives and allowlisting
Blocklists are broad, and sometimes they block a domain that a page or a device feature needs. The fix is an allowlist entry for the affected domain. The query log helps here: find the blocked lookup that corresponds to the broken feature, allow that domain, and retest. Make one change at a time so you know which entry solved the problem.
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Setup depends on your router and devices
The article describes the concept: run Pi-hole on a host that is always available, then point your network’s DNS to it. It does not give installation steps, and the exact method depends on your router and devices. Some routers let you set the DNS server once for every device that gets an address from the router. Others do not, so you would set DNS on each device or use a different approach. Check your router’s DHCP or DNS settings before changing anything, and keep a fallback DNS server configured so a failure does not cut off the whole network.
Who this setup suits
- Households with smart TVs, streaming boxes, or appliances where you cannot install a blocker, and where you accept some telemetry-related app issues.
- Readers who want a log of which domains each device requests, and who will read it regularly.
- People willing to maintain a DNS server that other people in the house depend on, including recovering it when it fails.
It is a poor fit if you need complete ad removal on video platforms, want to inspect all traffic, or cannot tolerate a DNS outage while you fix the host.
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