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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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.
Browse by registry
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Countries with unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,302 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 204.235.140.0/23 | 512 | ARIN |  US | 2nd Feb 1995 |
| 204.235.16.0/20 | 4.1k | ARIN | US | 20th Jan 1995 |
| 204.235.174.0/23 | 512 | ARIN | US | 3rd Feb 1995 |
| 204.238.0.0/24 | 256 | ARIN | US | 9th Feb 1995 |
| 204.238.1.0/24 | 256 | ARIN | US | 9th Feb 1995 |
| 204.238.10.0/24 | 256 | ARIN | US | 9th Feb 1995 |
| 204.238.100.0/24 | 256 | ARIN | US | 2nd May 1995 |
| 204.238.102.0/24 | 256 | ARIN | US | 2nd May 1995 |
| 204.238.103.0/24 | 256 | ARIN | US | 2nd May 1995 |
| 204.238.105.0/24 | 256 | ARIN | US | 5th May 1995 |
| 204.238.106.0/24 | 256 | ARIN | US | 5th May 1995 |
| 204.238.11.0/24 | 256 | ARIN | US | 9th Feb 1995 |
| 204.238.110.0/24 | 256 | ARIN | US | 5th May 1995 |
| 204.238.111.0/24 | 256 | ARIN | US | 5th May 1995 |
| 204.238.114.0/24 | 256 | ARIN | US | 5th May 1995 |
| 204.238.115.0/24 | 256 | ARIN | US | 5th May 1995 |
| 204.238.116.0/24 | 256 | ARIN | US | 5th May 1995 |
| 204.238.118.0/24 | 256 | ARIN | US | 8th May 1995 |
| 204.238.119.0/24 | 256 | ARIN | US | 8th May 1995 |
| 204.238.12.0/24 | 256 | ARIN | US | 9th Feb 1995 |
| 204.238.121.0/24 | 256 | ARIN | US | 10th May 1995 |
| 204.238.122.0/24 | 256 | ARIN | US | 10th May 1995 |
| 204.238.123.0/24 | 256 | ARIN | US | 10th May 1995 |
| 204.238.124.0/24 | 256 | ARIN | US | 10th May 1995 |
| 204.238.125.0/24 | 256 | ARIN | US | 10th May 1995 |
| 204.238.126.0/24 | 256 | ARIN | US | 11th May 1995 |
| 204.238.127.0/24 | 256 | ARIN | US | 11th May 1995 |
| 204.238.13.0/24 | 256 | ARIN | US | 9th Feb 1995 |
| 204.238.130.0/24 | 256 | ARIN | US | 11th May 1995 |
| 204.238.131.0/24 | 256 | ARIN | US | 12th May 1995 |
| 204.238.132.0/24 | 256 | ARIN | US | 15th May 1995 |
| 204.238.133.0/24 | 256 | ARIN | US | 15th May 1995 |
| 204.238.134.0/24 | 256 | ARIN | US | 15th May 1995 |
| 204.238.135.0/24 | 256 | ARIN | US | 15th May 1995 |
| 204.238.136.0/24 | 256 | ARIN | US | 15th May 1995 |
| 204.238.137.0/24 | 256 | ARIN | US | 15th May 1995 |
| 204.238.138.0/24 | 256 | ARIN | US | 15th May 1995 |
| 204.238.139.0/24 | 256 | ARIN | US | 15th May 1995 |
| 204.238.14.0/24 | 256 | ARIN | US | 9th Feb 1995 |
| 204.238.140.0/24 | 256 | ARIN | US | 15th May 1995 |
| 204.238.142.0/24 | 256 | ARIN | US | 16th May 1995 |
| 204.238.143.0/24 | 256 | ARIN | US | 4th May 2018 |
| 204.238.144.0/24 | 256 | ARIN | US | 16th May 1995 |
| 204.238.145.0/24 | 256 | ARIN | US | 16th May 1995 |
| 204.238.147.0/24 | 256 | ARIN | US | 17th May 1995 |
| 204.238.148.0/24 | 256 | ARIN | US | 17th May 1995 |
| 204.238.149.0/24 | 256 | ARIN | US | 17th May 1995 |
| 204.238.15.0/24 | 256 | ARIN | US | 9th Feb 1995 |
| 204.238.151.0/24 | 256 | ARIN | US | 18th May 1995 |
| 204.238.154.0/24 | 256 | ARIN | US | 18th May 1995 |