(This is first of a 2 part series, where I explore pi-hole as a DNS caching solution-Here's Part 2)
I've had a Raspberry Pi 4 sitting idle for months, and finally decided to put it to good use by setting up Pi-hole for network-wide DNS caching and ad blocking. After less than a day of operation, I'm genuinely impressed with both the installation process and the results.
The Installation: Surprisingly Smooth
Setting up Pi-hole turned out to be one of the smoothest software installations I've experienced in recent memory. The entire process is handled by a single bash script:
curl -sSL https://install.pi-hole.net | bash
That's it! What impressed me most wasn't just the simplicity, but the thoroughness of the pre-installation checks. Before the script even attempted to install anything, it ran through a comprehensive validation process:
- Network connectivity tests
- DNS resolution verification
- Package manager status checks
- System requirements validation
- Port availability confirmation
This rigorous validation gave me real confidence that the installation would succeed. Too often, installation scripts fail halfway through, leaving you with a partially configured mess. Pi-hole's approach of "check everything first, then install" meant that once the green lights were all showing, the installation proceeded flawlessly.
Interestingly, what took the most time during the entire setup wasn't Pi-hole itself, but my initial attempt to use Docker. I'd assumed Docker would be the quick and easy route (as it usually is), but the Pi had some leftover Docker installations that needed cleaning up first - removing old docker, docker.io, and docker-compose packages was a messy affair. Then the Pi seemed to have issues with the Docker installation process itself. In the end, I abandoned the Docker approach and went with the native installation, which ironically turned out to be much faster and cleaner.
One lesser-known tip that made the physical setup even smoother: if you're running a Google mesh network, the routers with both WAN and LAN ports can easily be used as wifi-to-LAN bridges. Rather than connecting the Pi 4 via WiFi, I simply plugged it into the LAN port of one of the mesh routers. This eliminated the need for additional network switches and reduced latency by a few milliseconds by avoiding the WiFi overhead entirely.
Another major convenience: you don't need to update DNS settings on each individual device. A single configuration change at the router level does the job for the entire household. In Google mesh, I simply changed the DNS setting from "Automatic" to "Custom" and set the Pi 4's IP as the primary DNS server. This immediately moved all devices on the network to use Pi-hole without touching any individual device settings. The only exceptions are devices that explicitly force their own DNS (looking at you, certain smart TVs and streaming devices), but those are relatively rare.
The Results: Better Than Expected
After 23 hours of operation protecting our home network, the statistics are eye-opening:
DNS Query Volume: 100,000 requests in 23 hours
- That's roughly 4,350 DNS queries per hour from our household
- Averages out to about 72 queries per minute
- Shows just how chatty modern devices really are
Cache Performance: 70% cache hit rate
- Pi-hole is successfully caching DNS responses locally
- Reduces latency for frequently accessed domains
- Decreases load on upstream DNS servers
- Currently using Quad9 (9.9.9.9) as the upstream resolver - the only non-US DNS service I still trust in this day and age
Blocking Effectiveness: 8.5% of requests blocked
- More than 1 in 12 DNS requests were for ad/tracking domains
- That's 8,500 blocked requests in just 23 hours
- Represents a significant reduction in unwanted network traffic
System Performance: Negligible Impact
One concern with running Pi-hole on a Pi 4 was whether it would impact system performance. For context, here are the system specs:
robins@pi4:~ $ uname -a
Linux pi4 6.12.34+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.12.34-1+rpt1~bookworm
(2025-06-26) aarch64 GNU/Linux
robins@pi4:~ $ free -h
total used free shared buff/cache available
Mem: 3.7Gi 463Mi 1.7Gi 34Mi 1.6Gi 3.3Gi
Swap: 511Mi 0B 511Mi
The performance numbers are reassuring:
CPU Usage: Essentially zero load:
robins@pi4:~ $ uptime
10:39:33 up 23:04, 3 users, load average: 0.00, 0.00, 0.00
- Zero computational overhead even after 23+ hours of operation
- Pi 4 is more than capable of handling the workload
- Plenty of headroom for additional services
Memory Usage: Minimal footprint
- Pi-hole runs efficiently even on modest hardware
- No noticeable impact on system responsiveness
Honestly, the Pi 4 seems like overkill for this task. Given the minimal resource requirements, a Pi 2 (with the older Cortex-A7) would likely handle Pi-hole just fine, leaving the Pi 4 (with the more capable Cortex-A72) free for more power-hungry side projects. The beauty of Pi-hole is that it's so lightweight, you can run it on practically any Raspberry Pi model and still have resources to spare.
The Web Interface: Polished and Responsive
Pi-hole's web dashboard deserves special mention. It's:
- Fast and Responsive: Page loads are snappy, even on the Pi 4
- Live Updates: The dashboard shows real-time query statistics
- Well-Designed: Clean interface that makes data easy to understand
- Comprehensive: Detailed logs, statistics, and configuration options
The live dashboard is particularly satisfying to watch - seeing blocked queries in real-time gives you a visceral sense of how much unwanted traffic Pi-hole is filtering out.
Real-World Benefits
Beyond the statistics, the practical benefits are noticeable:
- Faster Browsing: Pages load quicker without ad network delays
- Cleaner Experience: Websites feel less cluttered
- Privacy Improvement: Reduced tracking across devices
- Bandwidth Savings: Less unwanted traffic on the network
One particular benefit I'm looking forward to testing: my network occasionally suffers from stuttering ping latencies. Instead of the usual 10ms responses, I'll sometimes see 100ms or even 1-second ping times that persist for minutes. During these episodes, streaming mostly works and browsing barely functions, but what really hurts is DNS resolution - especially for websites requiring multiple round-trips. With Pi-hole's 70% cache hit rate, those problematic periods should be noticeably less laggy since most DNS queries won't need to traverse the struggling network connection. More testing needed, but the potential is promising.
The ad filtering aspect wasn't my primary motivation, but it doesn't hurt either. For websites I frequent that provide genuinely good content - like Phoronix with their constant stream of quality tech updates - I've set up pass-throughs so they can rightfully earn the advertising revenue they deserve for their work. For projects like Pi-hole itself, I prefer the direct contribution route via donations. It's about supporting the creators and maintainers who provide value, whether through allowing ads or direct financial support.
Worth Supporting
The Pi-hole project has created something genuinely useful that "just works" out of the box. The quality of both the software and the installation experience makes this a project worth supporting financially. I'll definitely be making a donation to help ensure continued development.
Final Thoughts
Pi-hole represents the best kind of open-source software: it solves a real problem elegantly, installs without drama, and delivers measurable benefits immediately. If you have a spare Raspberry Pi lying around, setting up Pi-hole is an excellent way to put it to work improving your entire network's performance and privacy.
The fact that it blocked 8,500 unwanted requests in less than a day while using virtually no system resources makes it a clear win. Sometimes the best technology is the kind you set up once and then forget about - until you look at the statistics and realize how much work it's quietly doing in the background.
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