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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 23.181.104.0/24 | 256 | ARIN |  US | 11th Jun 2024 |
| 23.181.192.0/24 | 256 | ARIN | US | 20th Mar 2018 |
| 23.181.208.0/24 | 256 | ARIN | US | 10th Jun 2021 |
| 23.181.24.0/24 | 256 | ARIN | US | 11th Jun 2024 |
| 23.181.64.0/24 | 256 | ARIN | US | 19th Mar 2018 |
| 23.181.88.0/24 | 256 | ARIN | US | 11th Jun 2024 |
| 23.182.184.0/24 | 256 | ARIN | US | 24th Jun 2024 |
| 23.182.24.0/24 | 256 | ARIN | US | 18th Jun 2024 |
| 23.182.40.0/24 | 256 | ARIN | US | 20th Jun 2024 |
| 23.182.64.0/24 | 256 | ARIN | US | 26th Mar 2018 |
| 23.182.65.0/24 | 256 | ARIN | US | 8th Oct 2018 |
| 23.183.114.0/24 | 256 | ARIN | US | 8th Jul 2021 |
| 23.183.115.0/24 | 256 | ARIN | US | 8th Jul 2021 |
| 23.183.128.0/24 | 256 | ARIN | US | 21st Jun 2017 |
| 23.183.16.0/24 | 256 | ARIN | US | 1st Jul 2021 |
| 23.183.176.0/24 | 256 | ARIN | US | 13th Jul 2021 |
| 23.183.184.0/24 | 256 | ARIN | US | 11th Jul 2024 |
| 23.184.128.0/24 | 256 | ARIN | US | 23rd Jun 2017 |
| 23.184.16.0/24 | 256 | ARIN | US | 15th Jul 2021 |
| 23.184.192.0/24 | 256 | ARIN | US | 5th Apr 2018 |
| 23.184.216.0/24 | 256 | ARIN | US | 29th Jul 2024 |
| 23.184.232.0/24 | 256 | ARIN | US | 29th Jul 2024 |
| 23.185.128.0/24 | 256 | ARIN | US | 23rd Jun 2017 |
| 23.185.216.0/24 | 256 | ARIN | US | 5th Aug 2024 |
| 23.185.224.0/24 | 256 | ARIN | US | 18th Feb 2026 |
| 23.185.232.0/24 | 256 | ARIN | US | 6th Aug 2024 |
| 23.186.0.0/24 | 256 | ARIN | US | 2nd Feb 2026 |
| 23.186.176.0/24 | 256 | ARIN | US | 23rd Aug 2021 |
| 23.187.112.0/24 | 256 | ARIN | US | 26th Aug 2021 |
| 23.187.128.0/24 | 256 | ARIN | US | 23rd Jun 2017 |
| 23.187.168.0/24 | 256 | ARIN | US | 27th Aug 2024 |
| 23.187.209.0/24 | 256 | ARIN | US | 8th Nov 2024 |
| 23.188.192.0/24 | 256 | ARIN | US | 16th Apr 2018 |
| 23.188.21.0/24 | 256 | ARIN | US | 24th Sept 2021 |
| 23.188.40.0/24 | 256 | ARIN | US | 3rd Sept 2024 |
| 23.188.48.0/24 | 256 | ARIN | US | 10th Sept 2021 |
| 23.189.0.0/24 | 256 | ARIN | US | 29th Nov 2016 |
| 23.189.232.0/24 | 256 | ARIN | US | 13th Sept 2024 |
| 23.189.24.0/24 | 256 | ARIN | US | 5th Sept 2024 |
| 23.189.80.0/24 | 256 | ARIN | US | 18th Oct 2021 |
| 23.189.81.0/24 | 256 | ARIN | US | 18th Oct 2021 |
| 23.190.192.0/24 | 256 | ARIN | US | 18th Apr 2018 |
| 23.190.24.0/24 | 256 | ARIN | US | 13th May 2026 |
| 23.190.49.0/24 | 256 | ARIN | US | 24th Sept 2021 |
| 23.190.50.0/24 | 256 | ARIN | US | 24th Sept 2021 |
| 23.190.51.0/24 | 256 | ARIN | US | 24th Sept 2021 |
| 23.190.64.0/24 | 256 | ARIN | US | 17th Apr 2018 |
| 23.190.80.0/21 | 2k | ARIN | US | 30th Sept 2021 |
| 23.191.208.0/24 | 256 | ARIN | US | 14th Oct 2021 |
| 23.191.24.0/24 | 256 | ARIN | US | 4th Oct 2024 |