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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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.
Browse by registry
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Countries with the most unannounced blocks, largest first.
Unannounced blocks
85,346 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 23.152.36.0/24 | 256 | ARIN |  PR | 7th Jan 2026 |
| 23.153.0.0/24 | 256 | ARIN |  US | 6th Sept 2016 |
| 23.153.116.0/24 | 256 | ARIN | US | 10th Feb 2026 |
| 23.153.144.0/24 | 256 | ARIN | US | 31st Mar 2020 |
| 23.153.152.0/24 | 256 | ARIN | US | 18th May 2023 |
| 23.153.184.0/24 | 256 | ARIN | US | 19th May 2023 |
| 23.153.192.0/24 | 256 | ARIN | US | 24th Apr 2024 |
| 23.153.200.0/24 | 256 | ARIN | US | 22nd May 2023 |
| 23.153.208.0/24 | 256 | ARIN | US | 7th Apr 2020 |
| 23.153.209.0/24 | 256 | ARIN | US | 1st Apr 2021 |
| 23.153.72.0/24 | 256 | ARIN | US | 15th May 2023 |
| 23.153.88.0/24 | 256 | ARIN | US | 16th May 2023 |
| 23.153.92.0/24 | 256 | ARIN | US | 6th Feb 2026 |
| 23.154.100.0/24 | 256 | ARIN | US | 11th Mar 2026 |
| 23.154.120.0/24 | 256 | ARIN | US | 31st May 2023 |
| 23.154.152.0/24 | 256 | ARIN | US | 31st May 2023 |
| 23.154.156.0/24 | 256 | ARIN | US | 13th Mar 2026 |
| 23.154.177.0/24 | 256 | ARIN | US | 2nd Apr 2021 |
| 23.154.188.0/24 | 256 | ARIN | US | 16th Mar 2026 |
| 23.154.20.0/24 | 256 | ARIN | US | 2nd Mar 2026 |
| 23.154.200.0/24 | 256 | ARIN | US | 5th Jun 2023 |
| 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 |
| 23.155.12.0/24 | 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 |
| 23.155.56.0/24 | 256 | ARIN |  CA | 9th Jun 2023 |
| 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 |
| 23.156.160.0/24 | 256 | ARIN | CA | 22nd Oct 2018 |
| 23.156.232.0/24 | 256 | ARIN | CA | 28th Jun 2023 |
| 23.156.244.0/24 | 256 | ARIN | US | 20th Apr 2026 |
| 23.156.36.0/24 | 256 | ARIN | US | 9th Apr 2026 |
| 23.156.44.0/24 | 256 | ARIN |  SG | 9th Apr 2026 |