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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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.
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Countries with unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,295 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 23.143.220.0/24 | 256 | ARIN |  US | 12th Aug 2025 |
| 23.143.240.0/24 | 256 | ARIN | US | 16th Oct 2019 |
| 23.143.244.0/24 | 256 | ARIN | US | 18th Aug 2025 |
| 23.143.252.0/24 | 256 | ARIN | US | 18th Aug 2025 |
| 23.143.68.0/24 | 256 | ARIN | US | 1st Aug 2025 |
| 23.144.0.0/24 | 256 | ARIN | US | 12th Oct 2015 |
| 23.144.136.0/24 | 256 | ARIN | US | 9th Dec 2022 |
| 23.144.140.0/24 | 256 | ARIN | US | 25th Aug 2025 |
| 23.144.180.0/24 | 256 | ARIN | US | 28th Aug 2025 |
| 23.144.200.0/24 | 256 | ARIN | US | 19th Dec 2022 |
| 23.144.208.0/24 | 256 | ARIN | US | 25th Oct 2019 |
| 23.144.232.0/24 | 256 | ARIN | US | 21st Dec 2022 |
| 23.144.252.0/24 | 256 | ARIN | US | 4th Sept 2025 |
| 23.144.52.0/24 | 256 | ARIN | US | 20th Aug 2025 |
| 23.144.76.0/24 | 256 | ARIN | US | 20th Aug 2025 |
| 23.145.140.0/24 | 256 | ARIN | US | 15th Sept 2025 |
| 23.145.168.0/24 | 256 | ARIN | US | 5th Jan 2023 |
| 23.145.56.0/24 | 256 | ARIN | US | 29th Dec 2022 |
| 23.145.57.0/24 | 256 | ARIN | US | 6th Nov 2023 |
| 23.145.84.0/24 | 256 | ARIN | US | 20th Feb 2026 |
| 23.145.88.0/24 | 256 | ARIN | US | 29th Dec 2022 |
| 23.146.108.0/24 | 256 | ARIN | US | 1st Oct 2025 |
| 23.146.112.0/24 | 256 | ARIN | US | 20th Nov 2019 |
| 23.146.12.0/24 | 256 | ARIN | US | 24th Sept 2025 |
| 23.146.148.0/24 | 256 | ARIN | US | 1st Oct 2025 |
| 23.146.17.0/24 | 256 | ARIN | US | 20th Apr 2020 |
| 23.146.18.0/24 | 256 | ARIN | US | 20th Apr 2020 |
| 23.146.184.0/24 | 256 | ARIN | US | 25th Jan 2023 |
| 23.146.20.0/24 | 256 | ARIN | US | 24th Sept 2025 |
| 23.146.208.0/24 | 256 | ARIN | US | 12th Dec 2019 |
| 23.146.217.0/24 | 256 | ARIN | US | 11th Dec 2024 |
| 23.146.252.0/24 | 256 | ARIN | US | 7th Oct 2025 |
| 23.146.52.0/24 | 256 | ARIN | US | 26th Sept 2025 |
| 23.146.60.0/24 | 256 | ARIN | US | 29th Sept 2025 |
| 23.146.92.0/24 | 256 | ARIN | US | 30th Sept 2025 |
| 23.147.124.0/24 | 256 | ARIN | US | 15th Oct 2025 |
| 23.147.132.0/24 | 256 | ARIN | US | 16th Oct 2025 |
| 23.147.192.0/24 | 256 | ARIN | US | 23rd Oct 2017 |
| 23.147.20.0/24 | 256 | ARIN | US | 8th Oct 2025 |
| 23.147.32.0/24 | 256 | ARIN | US | 29th Aug 2018 |
| 23.148.0.0/24 | 256 | ARIN | US | 9th Dec 2015 |
| 23.148.100.0/24 | 256 | ARIN | US | 27th Oct 2025 |
| 23.148.148.0/24 | 256 | ARIN | US | 29th Oct 2025 |
| 23.148.156.0/24 | 256 | ARIN | US | 29th Oct 2025 |
| 23.148.168.0/24 | 256 | ARIN | US | 27th Feb 2023 |
| 23.148.172.0/24 | 256 | ARIN | US | 29th Oct 2025 |
| 23.148.40.0/24 | 256 | ARIN | US | 15th Feb 2023 |
| 23.149.132.0/24 | 256 | ARIN | US | 13th Nov 2025 |
| 23.149.164.0/24 | 256 | ARIN | US | 13th Nov 2025 |
| 23.149.188.0/24 | 256 | ARIN | US | 14th Nov 2025 |