Summary
I have a network-wide privacy setup for my home network that works beautifully until it doesn’t. Pi-hole blocked trackers on my laptops and phones, but the same aggressive lists periodically break smart TVs, delay camera notifications, or leave a cloud-dependent bulb hanging off the internet. This left me in a loop of allowing one mysterious hostname, testing again, and repeating until the device came back online. So I decided to give my smart-home network its own DNS policy, and the constant tug-of-war disappeared overnight. Pi-hole blocks everything, including your smart bulb’s will to live Your phone can show an error, your bulb just silently gives up The problem wasn’t DNS blocking itself. DNS-level filters are excellent for devices that cannot run browser extensions or privacy apps, as a resolver can refuse to return an address for a tracking or malicious domain, stopping the connection before it starts. Pi-hole and AdGuard Home apply this protection across a network without requiring client software, which makes them rather useful when it comes to IoT devices. That said, you’ll run into problems if you use one blanket policy for every device. My phone can tolerate strict blocklists because I can see an error, inspect the query log, and work around it. A smart bulb, however, cannot explain that its login endpoint, telemetry host, and command service sit behind related domains. If any of those domains is blocked, it just stops responding. Relaxing your filters for everything will get the device back online, but it weakens security for devices that benefited from the stronger blocklists in the first place. Your smart home gets its own DNS lane, and the chaos stops Different devices, different policies, same hardware if you’re lazy My solution was to treat smart-home devices as a class of their own. They already live on an isolated 2.4 GHz network, so I assigned that network a dedicated DNS resolver. A separate physical server is optional here; another Pi-hole or AdGuard Home container, VM, or instance on existing hardware works just as well. The difference is the policy, not the service running it. The router’s DHCP service advertises the IoT resolver only to clients on that specific network, while my trusted network continues using the stricter resolver. Pi-hole can also assign clients to groups with different lists and rules, so the same result is possible with one instance if the resolver can reliably identify each client. AdGuard Home also supports client-specific settings and domain-specific upstream resolvers. This separation gives you a sane default. Computers and phones keep aggressive ad, malware, and tracking protection while smart home devices get a smaller, security-focused blocklist in addition to explicit blocks for tested telemetry domains that don’t break my devices. If a vendor endpoint is required for setup, authentication, notifications, or firmware checks, I allow it only on the IoT policy. I no longer have to punch a network-wide hole to revive one temperamental smart plug. Query logs finally matter when they’re only about your gadgets Find the one domain your smart plug needs, then stop guessing The biggest hassle of this approach is that there’s no universal blocklist you can download off the internet and use here. The domains you end up blocking will be specific to the smart devices you have around the house, so you’re going to have to dig through the logs. The upside is that instead of searching through thousands of queries from browsers, apps, and operating systems, you can see exactly what your smart devices request around the time a feature failed. Then, you can temporarily disable filtering for that client, reproduce the problem, compare the results, and allow only the minimum necessary domain. That doesn’t make every query malicious or prove what data a device sends. DNS reveals the hostnames a device tries to reach, not the contents of an encrypted connection. Still, the smaller dataset makes patterns obvious, such as repeated telemetry lookups, unexpected third-party services, or a device that keeps contacting the cloud even when you control it locally. DNS filtering can be a useful control point, but it complements LAN rules and outbound firewall restrictions instead of simply replacing them. Names beat numbers: ha.home.arpa instead of 192.168.something RFC 8375 gave your LAN a suffix, and .local can stay out of it A side benefit of running a dedicated smart-home resolver is that I also made it authoritative for internal names. This means that instead of typing an IP address and port number every time I wanted to access a service, I can now use URLs like ha.home.arpa for Home Assistant, mqtt.home.arpa for my MQTT broker, and so on. Both Pi-hole and AdGuard Home support local records or DNS rewrites that map a hostname to a LAN address. I used home.arpa on purpose. RFC 8375 reserves it for non-unique naming inside residential networks and says those queries should be answered locally rather than forwarded onto the internet. This also saved me the hassle of inventing a suffix and didn’t overload .local, which belongs to multicast DNS and is supposed to be resolved on the local link using mDNS. Internal naming also removed hard-coded IP addresses from dashboards, scripts, and Home Assistant integrations. If I move a service to another host, I update one DNS record instead of scanning through configuration files. DNS rewrites can also provide split-horizon behavior, where the same public hostname resolves to a private address at home and its public address elsewhere, a common pattern for Home Assistant setups. Congratulations, you now run critical infrastructure Backups, a second resolver, and IoT devices that ignore you anyway The biggest problem with this approach is the fact that a dedicated resolver quickly becomes infrastructure you have to maintain. It needs a stable address, backups, monitored storage, and preferably a second resolver. Advertising a public resolver as secondary is not a clean failover, as clients may use either server and end up bypassing local filtering or internal names. Both advertised addresses should therefore enforce the same local policy. Some IoT products also use hard-coded resolvers or encrypted DNS. I ended up handling ordinary external DNS with firewall rules that redirect or block port 53 from the IoT LAN, but encrypted DNS requires more intentional controls and can be difficult to separate from regular HTTPS traffic. IPv6 also needs attention, since an overlooked router advertisement can hand devices a resolver that bypasses the IPv4 setup. Privacy works better when it isn’t one-size-fits-nobody A looser smart-home policy made the whole network safer, somehow In the end, the biggest improvement isn’t blocking more domains, it was accepting that privacy controls should match the device. My smart home DNS is intentionally less aggressive, yet the overall network is more private because I no longer weaken the main policy whenever an appliance breaks. At the same time, local service names make setup and access easier to move, document, and repair. DNS won’t suddenly make shady devices trustworthy, but it does give you clearer boundaries, a focused log, and a controlled place to decide what each device may resolve. That small architectural change finally allows reliability and privacy to coexist instead of taking turns breaking each other.