{"id":7238,"date":"2026-11-07T19:29:18","date_gmt":"2026-11-07T18:29:18","guid":{"rendered":"https:\/\/www.pschatzmann.ch\/home\/?p=7238"},"modified":"2026-11-07T19:49:05","modified_gmt":"2026-11-07T18:49:05","slug":"the-cheapest-dns-server-you-will-ever-own","status":"publish","type":"post","link":"https:\/\/www.pschatzmann.ch\/home\/2026\/11\/07\/the-cheapest-dns-server-you-will-ever-own\/","title":{"rendered":"The Cheapest DNS Server You Will Ever Own"},"content":{"rendered":"

How a microcontroller the size of a postage stamp can name, find, and resolve everything on your network.<\/em><\/p>\n

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Names are the quiet superpower of networks<\/h2>\n

Every time you type a web address, an invisible conversation happens. Your device asks, “Where does this name live?” and somebody answers with a number. That somebody is a DNS server, and we usually imagine it as serious infrastructure: a rack in a data center, a router with a big brand name, a Raspberry Pi running a full Linux stack.<\/p>\n

What if the answer could come from a few-dollar microcontroller that sips power and boots in a blink?<\/p>\n

That is the idea behind two small Arduino libraries: TinyDNS<\/strong> and TinymDNS<\/strong>. Together they turn hobby-grade hardware into a real participant in the naming system of your network.<\/p>\n

Why another library? Because “it depends on your board” is a bad answer<\/h2>\n

Some platforms already ship a piece of this puzzle in their network stack. One core may offer mDNS, another a bare-bones resolver, and a third nothing at all. Each has its own API, its own quirks, and its own gaps. Move your project from one board to another and suddenly your names stop working.<\/p>\n

TinyDNS and TinymDNS are built on a different goal: the same full functionality, on every Arduino implementation.<\/strong> They don’t depend on anything the platform stack happens to provide. They only ask for what every Arduino network stack already has: a Client<\/code> for DNS, or a UDP<\/code> object for mDNS. Hand them whatever your board uses, and the behavior is the same.<\/p>\n

Write it once. Run it anywhere. That’s the promise.<\/p>\n

TinyDNS: a DNS server that fits in your pocket<\/h2>\n

TinyDNS is a header-only DNS library with two personalities.<\/p>\n

The client<\/strong> asks questions. It resolves hostnames into IPv4 and IPv6 addresses, and it does so over any network connection your board can open. That includes plain DNS over TCP and DNS over TLS<\/strong>, so your queries can travel encrypted instead of in the clear. A tiny device that cares about privacy: not bad.<\/p>\n

The server<\/strong> answers them. It keeps a static table of hostnames you define, remembers recent answers in a cache that forgets the least recently used entries first, and quietly forwards everything it doesn’t know to an upstream resolver. In other words, it behaves like the DNS service you’d expect from a home router, only you wrote the rules.<\/p>\n

Think about what that makes possible:<\/p>\n