Twelve games about how the network works. Every one of them is a short question with a real answer, and every answer comes from a source rather than from a guess: the IANA registries, the RIR allocation data, a routing table, or a name an operator wrote about its own router.
Most of them have a daily round — the same puzzle for everyone, so two people can argue about it — and practice rounds after that. Nothing is looked up while a page loads, nothing is stored on the server, and your score lives in your own browser. A finished round can be turned into a link that hands someone else the same puzzle to beat.
Eight IP addresses. Seven of them are real and routable; one was reserved by an RFC and can never be on the public internet. Fourteen grids, sixty seconds, and a wrong tap costs you two of them. The grid itself is the picture you post, so the puzzle travels without the website.
One address a day. Guess the country it belongs to.
One address a day. Guess which operator announces it.
A mystery address, and the round-trip time to it from five cities. Each time implies a maximum distance — a latency bounds a distance, it never names a place.
Who was handed this /8? A /8 is 16.7 million addresses, and the map of who holds them is a map of how the internet was allocated.
CIDR practice against the clock. A mask is a cut in the bit string, and the game makes you see where the cut falls.
Which country has more IPv4? Switch the mode and the answer can change — a country can hold one enormous block or ten thousand small ones.
Is this address on the public internet, or did an RFC set it aside? Answered from the IANA special-purpose address registry, and the RFC that reserved the block is named when you answer.
A routing table and one address. Which line does the router use? Not the first one it finds — the one that matches the most bits.
Two ways of writing an address. Octal, hexadecimal, short forms — are they the same host? The arithmetic is worked out in the reveal.
Read a router's PTR name like an operator
does. ae-1.a02.frnkge13.de.bb.gin.ntt.net is a sentence about
a router in Frankfurt.
A stamp for every country you look up, kept in your browser.
Nothing in the arcade is made up:
And when a question needs a live lookup — a route, a DNS record, a certificate — that is a tool, not a game. The two are kept apart on purpose.