How Pi-hole Works
Pi-hole runs as a DNS resolver on a device on your local network — a Raspberry Pi, a spare PC, a Docker container, or a VM. You configure your router to hand out Pi-hole's IP as the DNS server via DHCP. Every DNS query from every device on the network goes to Pi-hole first.
Pi-hole maintains a blocklist of known advertising, tracking, and malware domains (compiled from community-maintained lists like StevenBlack, AdGuard, and others — typically 100,000–1,000,000+ domains). When a device queries a blocked domain (e.g., doubleclick.net, ads.facebook.com), Pi-hole returns 0.0.0.0 (a null address) instead of the real IP. The device gets no valid IP for the ad server, so the request never goes out. For non-blocked domains, Pi-hole forwards the query upstream to your configured DNS resolver (1.1.1.1, 8.8.8.8, or your ISP's DNS).
What Pi-hole Blocks
- Display advertising: Banner ads, video prerolls, and tracking pixels served from dedicated ad domains.
- Third-party trackers: Analytics platforms (Google Analytics, Mixpanel, Hotjar), fingerprinting scripts, and retargeting pixels.
- Telemetry: Windows telemetry endpoints, smart TV usage reporting, IoT device call-home traffic — all configurable via specific blocklists.
- Malware domains: Known C2 servers, phishing domains, and malware distribution URLs included in security-focused blocklists.
- Coin mining scripts: Browser-based cryptomining domains.
What Pi-hole Cannot Block
- First-party ads: YouTube, Spotify, Hulu, and Peacock serve ads from their own domains — indistinguishable from content at the DNS level. DNS blocking cannot affect them.
- HTTPS content: Pi-hole only sees the domain being queried, not the URL path or content. It cannot block specific pages or content within a domain.
- Encrypted DNS bypass: Apps that hardcode DNS-over-HTTPS servers (Firefox with DoH, some Android apps using 8.8.8.8 directly) bypass Pi-hole entirely. Workarounds include blocking DoH providers at the firewall or using Pi-hole's DNS-over-HTTPS support.
- Devices using hardcoded DNS: Some smart TVs and IoT devices ignore DHCP-assigned DNS and query 8.8.8.8 directly. These bypass Pi-hole unless you redirect port 53 traffic to Pi-hole via router NAT rules.
Pi-hole vs Browser Extensions
| Feature | Pi-hole | uBlock Origin |
|---|---|---|
| Scope | Whole network, all devices | One browser on one device |
| YouTube/Spotify ads | No | Yes (HTTP-level) |
| Cosmetic filtering | No | Yes (hides ad placeholders) |
| Smart TV / IoT coverage | Yes | No |
| Query logging / visibility | Yes — full DNS log | No |
| Setup complexity | Moderate (server required) | Trivial (browser install) |
The two are complementary: Pi-hole for network-wide domain blocking, uBlock Origin for browser-level element filtering including YouTube ads.
Security Benefits Beyond Ad Blocking
Pi-hole's DNS logging gives you full visibility into what every device on your network is querying. This is genuinely useful for security: spotting an IoT device calling home to an unexpected country's IP, detecting malware C2 traffic from a compromised device, or identifying an app that queries dozens of tracking domains on every launch. The query log is a free network monitoring tool.
Frequently Asked Questions
Does Pi-hole block ads inside YouTube or Spotify?
No. These services serve ads from the same domains as their content. DNS-level blocking cannot distinguish ad traffic from content traffic on the same domain. Browser extensions like uBlock Origin that operate at the HTTP level can block YouTube ads; Pi-hole cannot.
Does Pi-hole replace a VPN?
No — they do different things. Pi-hole blocks specific domains at DNS level on your local network. A VPN encrypts and routes traffic through a different server, changing your IP and protecting traffic from local observers. Pi-hole provides no encryption, no IP masking, and no protection outside your home network. They work well together.