Allocated but unannounced space
Every block here was allocated or assigned by a regional internet registry, and none of them appeared in any routing table we collected at our last snapshot — neither as a route of their own, nor covered by a larger announcement, nor carved up into more specifics.
“Unannounced” does not mean “unused”
Plenty of allocated space is deliberately kept off the public internet: private interconnects, lab and lawful-intercept ranges, networks reachable only inside one operator, and space held in reserve. Some of it is announced somewhere our collectors cannot see, which is a limit of our vantage points rather than a fact about the block.
It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today. Nothing on this page means a block is unallocated, available, or free to announce.
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Countries with unannounced space registered through ARIN, largest first.
Unannounced blocks in Japan
15 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 199.103.103.0/24 | 256 | ARIN |  JP | 25th Jun 1994 |
| 204.231.230.0/24 | 256 | ARIN | JP | 21st Apr 1995 |
| 204.231.251.0/24 | 256 | ARIN | JP | 21st Apr 1995 |
| 204.231.252.0/24 | 256 | ARIN | JP | 21st Apr 1995 |
| 204.79.157.0/24 | 256 | ARIN | JP | 14th Dec 1994 |
| 204.79.158.0/24 | 256 | ARIN | JP | 14th Dec 1994 |
| 204.79.218.0/24 | 256 | ARIN | JP | 19th Dec 1994 |
| 2602:f75d::/36 | 268M × /64 | ARIN | JP | 19th Dec 2024 |
| 2602:f780::/36 | 268M × /64 | ARIN | JP | 27th Nov 2024 |
| 2602:f796::/40 | 16.8M × /64 | ARIN | JP | 18th Nov 2024 |
| 2602:f7a9::/36 | 268M × /64 | ARIN | JP | 7th Nov 2024 |
| 2602:f840::/36 | 268M × /64 | ARIN | JP | 14th Aug 2024 |
| 2602:fec7::/40 | 16.8M × /64 | ARIN | JP | 23rd Jan 2026 |
| 2602:fece::/40 | 16.8M × /64 | ARIN | JP | 23rd Jan 2026 |
| 2602:ff22::/40 | 16.8M × /64 | ARIN | JP | 27th Jan 2026 |