The round of 2026-10-23 — the same fourteen grids for everyone.
Eight IP addresses. Seven of them are real — they route on the public internet right now, and somebody announced them. One of them cannot exist out there at all: an RFC set that space aside for something else. Find the one that cannot.
There are 14 of these grids and 60 seconds for all of them. A wrong tap costs you 2 seconds, and the answer is always shown — a fact worth reading is the whole point. Find all 14 and you have seen every reserved block this site knows about.
This is built to be shared: the grid below is the picture that gets posted, and whoever sees it can answer it without opening anything. The odd one out is always a real fact — a loopback address, a private network, a documentation range — and the reveal names the RFC that reserved it.
Which one can never be on the internet?
Time 60 s
Tap the one that cannot be on the internet.
Found 0 of 14 blocks
Grid 1 of 14 · best today — · all time —
Kept in this browser only; the server never sees a score.
What the answer was
——These are the reserved ranges, and what each one is actually for. A block being reserved says what the address space is for — not who is using an address inside it today. A run of the game shows all 14 of them, once each.
10.0.0.0/8,
172.16.0.0/12, 192.168.0.0/16 — RFC 1918. What a
router hands out behind your front door. Not routed on the public
internet, so an address in one identifies a device, not a service.
127.0.0.0/8
— RFC 1122. Every address in it means "this machine".
127.0.0.1 is your computer talking to itself, and it never
leaves.
169.254.0.0/16
— RFC 3927. "This link". A machine that cannot reach a DHCP server
picks an address here, which is why a failed address often starts with
169.254.
100.64.0.0/10
— RFC 6598. Shared address space: an ISP hands the same addresses to
thousands of customers and maps them with NAT.
192.0.2.0/24,
198.51.100.0/24, 203.0.113.0/24 — RFC 5737.
Reserved so examples in a manual can use a real-looking address that
can never belong to anyone.
198.18.0.0/15
is for load tests, 240.0.0.0/4 was reserved for a future
that never came, and 0.0.0.0/8 means "this network" —
before an address is known at all.
The reserved blocks come from the IANA IPv4 Special-Purpose Address Registry and its IPv6 counterpart. Corpus: IANA IPv4 and IPv6 Special-Purpose Address Registry, frozen 2026-10-21. Nothing is looked up while this page loads.