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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,273 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 142.248.4.0/22 | 1k | ARIN |  US | 10th Oct 2025 |
| 142.248.47.0/24 | 256 | ARIN | US | 10th Oct 2025 |
| 142.248.48.0/22 | 1k | ARIN | US | 10th Oct 2025 |
| 142.248.63.0/24 | 256 | ARIN | US | 10th Oct 2025 |
| 142.248.72.0/22 | 1k | ARIN | US | 10th Oct 2025 |
| 142.248.76.0/22 | 1k | ARIN | US | 10th Oct 2025 |
| 142.248.92.0/23 | 512 | ARIN | US | 10th Oct 2025 |
| 142.248.95.0/24 | 256 | ARIN | US | 14th Oct 2025 |
| 142.249.108.0/23 | 512 | ARIN | US | 9th Oct 2025 |
| 142.249.110.0/24 | 256 | ARIN | US | 25th Nov 2025 |
| 142.249.116.0/22 | 1k | ARIN | US | 9th Oct 2025 |
| 142.249.126.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.132.0/22 | 1k | ARIN | US | 9th Oct 2025 |
| 142.249.152.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.155.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.158.0/24 | 256 | ARIN | US | 4th Dec 2025 |
| 142.249.160.0/22 | 1k | ARIN | US | 9th Oct 2025 |
| 142.249.172.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.173.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.175.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.192.0/22 | 1k | ARIN | US | 9th Oct 2025 |
| 142.249.196.0/22 | 1k | ARIN | US | 10th Oct 2025 |
| 142.249.223.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.228.0/22 | 1k | ARIN | US | 9th Oct 2025 |
| 142.249.236.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.240.0/22 | 1k | ARIN | US | 9th Oct 2025 |
| 142.249.244.0/22 | 1k | ARIN | US | 9th Oct 2025 |
| 142.249.248.0/22 | 1k | ARIN | US | 9th Oct 2025 |
| 142.249.30.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.35.0/24 | 256 | ARIN | US | 13th Oct 2025 |
| 142.249.40.0/22 | 1k | ARIN | US | 9th Oct 2025 |
| 142.249.44.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.46.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.47.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.64.0/22 | 1k | ARIN | US | 9th Oct 2025 |
| 142.249.68.0/22 | 1k | ARIN | US | 9th Oct 2025 |
| 142.249.88.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.90.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.91.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.93.0/24 | 256 | ARIN | US | 13th Oct 2025 |
| 142.249.94.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.249.95.0/24 | 256 | ARIN | US | 9th Oct 2025 |
| 142.254.128.0/17 | 32.8k | ARIN | US | 15th Jun 2012 |
| 142.255.128.0/18 | 16.4k | ARIN | US | 9th Jul 2012 |
| 142.4.224.0/19 | 8.2k | ARIN | US | 8th Aug 2012 |
| 142.54.0.0/21 | 2k | ARIN | US | 13th May 1991 |
| 142.54.16.0/23 | 512 | ARIN | US | 13th May 1991 |
| 142.88.0.0/16 | 65.5k | ARIN | US | 6th Jun 1994 |
| 143.122.0.0/16 | 65.5k | ARIN | US | 19th Sept 1990 |
| 143.131.128.0/19 | 8.2k | ARIN | US | 19th Sept 1990 |