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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,251 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 40.238.0.0/16 | 65.5k | ARIN |  US | 4th Dec 2023 |
| 40.239.0.0/16 | 65.5k | ARIN | US | 28th Sept 2022 |
| 40.24.0.0/16 | 65.5k | ARIN | US | 23rd Apr 1991 |
| 40.240.0.0/16 | 65.5k | ARIN | US | 23rd Apr 1991 |
| 40.241.0.0/16 | 65.5k | ARIN | US | 28th Jul 2022 |
| 40.242.0.0/16 | 65.5k | ARIN | US | 28th Jul 2022 |
| 40.243.0.0/16 | 65.5k | ARIN | US | 23rd Apr 1991 |
| 40.244.0.0/14 | 262k | ARIN | US | 23rd Apr 1991 |
| 40.26.0.0/16 | 65.5k | ARIN | US | 23rd Apr 1991 |
| 40.36.0.0/15 | 131k | ARIN | US | 23rd Apr 1991 |
| 40.40.0.0/14 | 262k | ARIN | US | 23rd Apr 1991 |
| 40.46.0.0/16 | 65.5k | ARIN | US | 23rd Apr 1991 |
| 40.49.0.0/16 | 65.5k | ARIN | US | 23rd Apr 1991 |
| 40.50.0.0/15 | 131k | ARIN | US | 23rd Apr 1991 |
| 40.57.0.0/16 | 65.5k | ARIN | US | 23rd Apr 1991 |
| 45.0.0.0/15 | 131k | ARIN | US | 9th Sept 1991 |
| 45.132.80.0/22 | 1k | ARIN | US | 21st Jan 2025 |
| 45.154.219.0/24 | 256 | ARIN | US | 11th Apr 2022 |
| 45.159.108.0/24 | 256 | ARIN | US | 13th Oct 2025 |
| 45.33.194.0/24 | 256 | ARIN | US | 19th Nov 2020 |
| 45.33.197.0/24 | 256 | ARIN | US | 5th Mar 2019 |
| 45.34.0.0/15 | 131k | ARIN | US | 6th Dec 2023 |
| 45.40.16.0/20 | 4.1k | ARIN | US | 26th Feb 2015 |
| 45.41.194.0/24 | 256 | ARIN | US | 9th Jul 2021 |
| 45.41.195.0/24 | 256 | ARIN | US | 29th Jul 2021 |
| 45.41.20.0/22 | 1k | ARIN | US | 8th Jul 2021 |
| 45.41.248.0/22 | 1k | ARIN | US | 7th Jul 2021 |
| 45.41.32.0/22 | 1k | ARIN | US | 15th Jul 2021 |
| 45.41.36.0/24 | 256 | ARIN | US | 2nd Oct 2026 |
| 45.41.39.0/24 | 256 | ARIN | US | 3rd Oct 2024 |
| 45.42.164.0/22 | 1k | ARIN | US | 8th Jan 2021 |
| 45.42.196.0/24 | 256 | ARIN | US | 2nd Feb 2021 |
| 45.42.199.0/24 | 256 | ARIN | US | 2nd Jun 2021 |
| 45.42.213.0/24 | 256 | ARIN | US | 1st Apr 2021 |
| 45.42.249.0/24 | 256 | ARIN | US | 6th Apr 2021 |
| 45.45.140.0/22 | 1k | ARIN | US | 7th Jul 2021 |
| 45.45.149.0/24 | 256 | ARIN | US | 14th Jul 2021 |
| 45.45.150.0/24 | 256 | ARIN | US | 21st Jul 2021 |
| 45.45.156.0/24 | 256 | ARIN | US | 31st Jul 2026 |
| 45.45.157.0/24 | 256 | ARIN | US | 21st Jul 2021 |
| 45.45.192.0/24 | 256 | ARIN | US | 10th Aug 2021 |
| 45.56.192.0/23 | 512 | ARIN | US | 28th Sept 2016 |
| 45.56.194.0/24 | 256 | ARIN | US | 28th Sept 2016 |
| 45.56.196.0/22 | 1k | ARIN | US | 28th Sept 2016 |
| 45.59.159.0/24 | 256 | ARIN | US | 5th Jan 2022 |
| 45.59.166.0/24 | 256 | ARIN | US | 8th Jul 2021 |
| 45.59.180.0/22 | 1k | ARIN | US | 29th Sept 2023 |
| 45.62.48.0/20 | 4.1k | ARIN | US | 16th Jan 2015 |
| 45.74.152.0/22 | 1k | ARIN | US | 27th May 2026 |
| 45.74.160.0/20 | 4.1k | ARIN | US | 23rd Apr 2015 |