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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 23.154.216.0/24 | 256 | ARIN |  US | 5th Jun 2023 |
| 23.154.244.0/24 | 256 | ARIN | US | 18th Mar 2026 |
| 23.154.52.0/24 | 256 | ARIN | US | 3rd Mar 2026 |
| 23.154.60.0/24 | 256 | ARIN | US | 3rd Mar 2026 |
| 23.154.68.0/24 | 256 | ARIN | US | 6th Mar 2026 |
| 23.154.88.0/24 | 256 | ARIN | US | 26th May 2023 |
| 23.155.100.0/24 | 256 | ARIN | US | 31st Mar 2026 |
| 23.155.104.0/24 | 256 | ARIN | US | 13th Jun 2023 |
| 23.155.112.0/24 | 256 | ARIN | US | 23rd Apr 2020 |
| 23.155.12.0/24 | 256 | ARIN | US | 18th Mar 2026 |
| 23.155.120.0/24 | 256 | ARIN | US | 13th Jun 2023 |
| 23.155.140.0/24 | 256 | ARIN | US | 31st Mar 2026 |
| 23.155.148.0/24 | 256 | ARIN | US | 2nd Apr 2026 |
| 23.155.164.0/24 | 256 | ARIN | US | 2nd Apr 2026 |
| 23.155.172.0/24 | 256 | ARIN | US | 2nd Apr 2026 |
| 23.155.232.0/24 | 256 | ARIN | US | 20th Jun 2023 |
| 23.155.244.0/24 | 256 | ARIN | US | 7th Apr 2026 |
| 23.155.36.0/24 | 256 | ARIN | US | 25th Mar 2026 |
| 23.155.60.0/24 | 256 | ARIN | US | 25th Mar 2026 |
| 23.155.68.0/24 | 256 | ARIN | US | 26th Mar 2026 |
| 23.155.76.0/24 | 256 | ARIN | US | 26th Mar 2026 |
| 23.155.80.0/24 | 256 | ARIN | US | 23rd Apr 2020 |
| 23.155.88.0/24 | 256 | ARIN | US | 12th Jun 2023 |
| 23.156.120.0/24 | 256 | ARIN | US | 23rd Jun 2023 |
| 23.156.244.0/24 | 256 | ARIN | US | 20th Apr 2026 |
| 23.156.36.0/24 | 256 | ARIN | US | 9th Apr 2026 |
| 23.156.52.0/24 | 256 | ARIN | US | 9th Apr 2026 |
| 23.156.56.0/24 | 256 | ARIN | US | 22nd Jun 2023 |
| 23.156.8.0/24 | 256 | ARIN | US | 20th Jun 2023 |
| 23.156.88.0/24 | 256 | ARIN | US | 23rd Jun 2023 |
| 23.156.92.0/24 | 256 | ARIN | US | 13th Apr 2026 |
| 23.157.124.0/24 | 256 | ARIN | US | 28th Apr 2026 |
| 23.157.132.0/24 | 256 | ARIN | US | 28th Apr 2026 |
| 23.157.140.0/24 | 256 | ARIN | US | 28th Apr 2026 |
| 23.157.16.0/24 | 256 | ARIN | US | 15th May 2020 |
| 23.157.180.0/24 | 256 | ARIN | US | 5th May 2026 |
| 23.157.196.0/24 | 256 | ARIN | US | 7th May 2026 |
| 23.157.20.0/24 | 256 | ARIN | US | 20th Apr 2026 |
| 23.157.212.0/24 | 256 | ARIN | US | 7th May 2026 |
| 23.157.224.0/24 | 256 | ARIN | US | 6th Nov 2018 |
| 23.157.228.0/24 | 256 | ARIN | US | 7th May 2026 |
| 23.157.36.0/24 | 256 | ARIN | US | 21st Apr 2026 |
| 23.157.44.0/24 | 256 | ARIN | US | 21st Apr 2026 |
| 23.157.64.0/24 | 256 | ARIN | US | 30th Nov 2017 |
| 23.157.8.0/24 | 256 | ARIN | US | 29th Jun 2023 |
| 23.157.80.0/24 | 256 | ARIN | US | 20th May 2020 |
| 23.157.96.0/24 | 256 | ARIN | US | 31st Oct 2018 |
| 23.158.108.0/24 | 256 | ARIN | US | 18th May 2026 |
| 23.158.12.0/24 | 256 | ARIN | US | 11th May 2026 |
| 23.158.156.0/24 | 256 | ARIN | US | 21st May 2026 |