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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 23.138.244.0/24 | 256 | ARIN |  US | 19th May 2025 |
| 23.138.52.0/24 | 256 | ARIN | US | 23rd Apr 2025 |
| 23.138.56.0/24 | 256 | ARIN | US | 1st Jul 2022 |
| 23.138.68.0/24 | 256 | ARIN | US | 23rd Apr 2025 |
| 23.138.92.0/24 | 256 | ARIN | US | 24th Apr 2025 |
| 23.139.0.0/24 | 256 | ARIN | US | 29th Jun 2016 |
| 23.139.12.0/24 | 256 | ARIN | US | 20th May 2025 |
| 23.139.168.0/24 | 256 | ARIN | US | 8th Aug 2022 |
| 23.139.180.0/24 | 256 | ARIN | US | 3rd Jun 2025 |
| 23.139.200.0/24 | 256 | ARIN | US | 12th Aug 2022 |
| 23.139.224.0/24 | 256 | ARIN | US | 3rd Jul 2018 |
| 23.139.244.0/24 | 256 | ARIN | US | 5th Jun 2025 |
| 23.139.28.0/24 | 256 | ARIN | US | 22nd May 2025 |
| 23.139.56.0/24 | 256 | ARIN | US | 22nd Jul 2022 |
| 23.139.68.0/24 | 256 | ARIN | US | 23rd May 2025 |
| 23.139.80.0/24 | 256 | ARIN | US | 25th Jul 2019 |
| 23.140.116.0/24 | 256 | ARIN | US | 23rd Jun 2025 |
| 23.140.12.0/24 | 256 | ARIN | US | 9th Jun 2025 |
| 23.140.140.0/24 | 256 | ARIN | US | 24th Jun 2025 |
| 23.140.172.0/24 | 256 | ARIN | US | 27th Jun 2025 |
| 23.140.196.0/24 | 256 | ARIN | US | 30th Jun 2025 |
| 23.140.32.0/24 | 256 | ARIN | US | 5th Jul 2018 |
| 23.140.56.0/24 | 256 | ARIN | US | 19th Aug 2022 |
| 23.141.108.0/24 | 256 | ARIN | US | 10th Jul 2025 |
| 23.141.140.0/24 | 256 | ARIN | US | 15th Jul 2025 |
| 23.141.152.0/24 | 256 | ARIN | US | 26th Sept 2022 |
| 23.141.16.0/24 | 256 | ARIN | US | 27th Aug 2019 |
| 23.141.184.0/24 | 256 | ARIN | US | 26th Sept 2022 |
| 23.141.192.0/24 | 256 | ARIN | US | 22nd Sept 2017 |
| 23.141.28.0/24 | 256 | ARIN | US | 2nd Jul 2025 |
| 23.141.32.0/24 | 256 | ARIN | US | 19th Jul 2018 |
| 23.141.56.0/24 | 256 | ARIN | US | 21st Sept 2022 |
| 23.141.60.0/24 | 256 | ARIN | US | 8th Jul 2025 |
| 23.142.104.0/24 | 256 | ARIN | US | 21st Oct 2022 |
| 23.142.146.0/24 | 256 | ARIN | US | 26th Jan 2024 |
| 23.142.148.0/24 | 256 | ARIN | US | 23rd Jul 2025 |
| 23.142.20.0/24 | 256 | ARIN | US | 18th Jul 2025 |
| 23.142.204.0/24 | 256 | ARIN | US | 25th Jul 2025 |
| 23.142.220.0/24 | 256 | ARIN | US | 28th Jul 2025 |
| 23.142.28.0/24 | 256 | ARIN | US | 18th Jul 2025 |
| 23.142.40.0/24 | 256 | ARIN | US | 19th Oct 2022 |
| 23.142.68.0/24 | 256 | ARIN | US | 21st Jul 2025 |
| 23.143.0.0/24 | 256 | ARIN | US | 12th Jul 2016 |
| 23.143.124.0/24 | 256 | ARIN | US | 6th Aug 2025 |
| 23.143.128.0/24 | 256 | ARIN | US | 14th Mar 2017 |
| 23.143.136.0/24 | 256 | ARIN | US | 15th Nov 2022 |
| 23.143.164.0/24 | 256 | ARIN | US | 7th Aug 2025 |
| 23.143.180.0/24 | 256 | ARIN | US | 7th Aug 2025 |
| 23.143.184.0/24 | 256 | ARIN | US | 18th Nov 2022 |
| 23.143.20.0/24 | 256 | ARIN | US | 31st Jul 2025 |