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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
Browse by country
Countries with the most unannounced blocks, largest first.
Unannounced blocks in United States
26,989 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 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 |
| 143.131.16.0/20 | 4.1k | ARIN | US | 19th Sept 1990 |