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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 23.131.48.0/24 | 256 | ARIN |  US | 8th Apr 2019 |
| 23.131.80.0/24 | 256 | ARIN | US | 10th Apr 2019 |
| 23.132.128.0/24 | 256 | ARIN | US | 9th Jan 2017 |
| 23.132.136.0/24 | 256 | ARIN | US | 25th Feb 2022 |
| 23.132.137.0/24 | 256 | ARIN | US | 25th Feb 2022 |
| 23.132.20.0/24 | 256 | ARIN | US | 8th Jan 2025 |
| 23.132.240.0/24 | 256 | ARIN | US | 1st May 2019 |
| 23.133.12.0/24 | 256 | ARIN | US | 23rd Jan 2025 |
| 23.133.128.0/24 | 256 | ARIN | US | 23rd Jan 2017 |
| 23.133.16.0/24 | 256 | ARIN | US | 1st May 2019 |
| 23.133.180.0/24 | 256 | ARIN | US | 3rd Feb 2025 |
| 23.133.36.0/24 | 256 | ARIN | US | 24th Jan 2025 |
| 23.133.44.0/24 | 256 | ARIN | US | 24th Jan 2025 |
| 23.133.6.0/24 | 256 | ARIN | US | 24th May 2016 |
| 23.133.92.0/24 | 256 | ARIN | US | 29th Jan 2025 |
| 23.133.96.0/24 | 256 | ARIN | US | 31st May 2018 |
| 23.134.100.0/24 | 256 | ARIN | US | 12th Feb 2025 |
| 23.134.116.0/24 | 256 | ARIN | US | 13th Feb 2025 |
| 23.134.132.0/24 | 256 | ARIN | US | 13th Feb 2025 |
| 23.134.204.0/24 | 256 | ARIN | US | 18th Feb 2025 |
| 23.134.40.0/24 | 256 | ARIN | US | 28th Mar 2022 |
| 23.134.56.0/24 | 256 | ARIN | US | 30th Mar 2022 |
| 23.134.80.0/24 | 256 | ARIN | US | 14th May 2019 |
| 23.135.172.0/24 | 256 | ARIN | US | 4th Mar 2025 |
| 23.135.180.0/24 | 256 | ARIN | US | 5th Mar 2025 |
| 23.135.188.0/24 | 256 | ARIN | US | 6th Mar 2025 |
| 23.135.204.0/24 | 256 | ARIN | US | 11th Mar 2025 |
| 23.135.225.0/24 | 256 | ARIN | US | 22nd Dec 2025 |
| 23.135.244.0/24 | 256 | ARIN | US | 13th Mar 2025 |
| 23.135.248.0/24 | 256 | ARIN | US | 4th May 2022 |
| 23.136.132.0/24 | 256 | ARIN | US | 27th Mar 2025 |
| 23.136.148.0/24 | 256 | ARIN | US | 28th Mar 2025 |
| 23.136.156.0/24 | 256 | ARIN | US | 28th Mar 2025 |
| 23.136.16.0/24 | 256 | ARIN | US | 4th Jun 2019 |
| 23.136.24.0/24 | 256 | ARIN | US | 9th May 2022 |
| 23.136.40.0/24 | 256 | ARIN | US | 9th May 2022 |
| 23.136.76.0/24 | 256 | ARIN | US | 19th Mar 2025 |
| 23.137.120.0/22 | 1k | ARIN | US | 10th Jun 2022 |
| 23.137.124.0/23 | 512 | ARIN | US | 10th Jun 2022 |
| 23.137.148.0/24 | 256 | ARIN | US | 14th Apr 2025 |
| 23.137.156.0/24 | 256 | ARIN | US | 14th Apr 2025 |
| 23.137.32.0/24 | 256 | ARIN | US | 20th Jun 2018 |
| 23.137.36.0/24 | 256 | ARIN | US | 8th Apr 2025 |
| 23.137.92.0/24 | 256 | ARIN | US | 10th Apr 2025 |
| 23.138.0.0/24 | 256 | ARIN | US | 22nd Feb 2016 |
| 23.138.108.0/24 | 256 | ARIN | US | 25th Apr 2025 |
| 23.138.168.0/24 | 256 | ARIN | US | 14th Jul 2022 |
| 23.138.172.0/24 | 256 | ARIN | US | 6th May 2025 |
| 23.138.220.0/24 | 256 | ARIN | US | 14th May 2025 |
| 23.138.232.0/24 | 256 | ARIN | US | 15th Jul 2022 |