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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 the most unannounced blocks, largest first.
Unannounced blocks in United States
26,993 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 40.215.0.0/16 | 65.5k | ARIN |  US | 23rd Apr 1991 |
| 40.217.0.0/16 | 65.5k | ARIN | US | 13th Feb 2023 |
| 40.219.0.0/16 | 65.5k | ARIN | US | 13th Feb 2023 |
| 40.22.0.0/15 | 131k | ARIN | US | 23rd Apr 1991 |
| 40.221.0.0/16 | 65.5k | ARIN | US | 13th Feb 2023 |
| 40.222.0.0/16 | 65.5k | ARIN | US | 13th Feb 2023 |
| 40.225.0.0/16 | 65.5k | ARIN | US | 23rd Apr 1991 |
| 40.230.0.0/16 | 65.5k | ARIN | US | 13th Feb 2023 |
| 40.233.128.0/17 | 32.8k | ARIN | US | 23rd Apr 1991 |
| 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 |
| 40.57.0.0/16 | 65.5k | ARIN | US | 23rd Apr 1991 |
| 45.0.0.0/15 | 131k | ARIN | US | 9th Sept 1991 |
| 45.11.244.0/22 | 1k | RIPE NCC | US | 30th Apr 2019 |
| 45.132.33.0/24 | 256 | RIPE NCC | US | 21st Apr 2020 |
| 45.147.52.0/22 | 1k | RIPE NCC | US | 30th Aug 2019 |
| 45.150.52.0/22 | 1k | ARIN | US | 21st Jan 2025 |
| 45.154.124.0/22 | 1k | RIPE NCC | US | 16th Sept 2019 |
| 45.154.219.0/24 | 256 | ARIN | US | 11th Apr 2022 |
| 45.159.108.0/24 | 256 | ARIN | US | 13th Oct 2025 |
| 45.159.216.0/22 | 1k | RIPE NCC | US | 2nd Oct 2019 |
| 45.250.72.0/22 | 1k | APNIC | US | 17th May 2016 |
| 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 |
| 45.41.39.0/24 | 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 |
| 45.42.224.0/24 | 256 | ARIN | US | 2nd Apr 2026 |
| 45.42.227.0/24 | 256 | ARIN | US | 1st Apr 2021 |
| 45.42.236.0/22 | 1k | ARIN | US | 2nd 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 |