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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,315 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 2001:506:6000::/35 | 537M × /64 | ARIN |  US | 22nd May 2013 |
| 2001:506:8::/48 | 65.5k × /64 | ARIN | US | 7th May 2008 |
| 2001:506:9::/48 | 65.5k × /64 | ARIN | US | 14th Oct 2020 |
| 2001:506::/48 | 65.5k × /64 | ARIN | US | 17th Jan 2007 |
| 2001:530::/32 | 4.3B × /64 | ARIN | US | 31st Oct 2002 |
| 2001:570::/32 | 4.3B × /64 | ARIN | US | 5th Feb 2003 |
| 2001:5d0::/32 | 4.3B × /64 | ARIN | US | 26th Mar 2003 |
| 2001:5d8::/32 | 4.3B × /64 | ARIN | US | 4th Apr 2003 |
| 2001:5f0::/32 | 4.3B × /64 | ARIN | US | 28th Apr 2003 |
| 201.19.0.0/16 | 65.5k | ARIN | US | 29th Jul 2026 |
| 201.29.0.0/16 | 65.5k | ARIN | US | 27th May 2026 |
| 201.32.128.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 201.4.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 201.50.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 201.51.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 201.78.0.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 201.78.224.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 201.8.0.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 201.8.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 201.8.32.0/20 | 4.1k | ARIN | US | 13th Mar 2025 |
| 201.89.128.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 201.9.0.0/16 | 65.5k | ARIN | US | 29th Jul 2026 |
| 201.94.0.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 202.27.250.0/24 | 256 | ARIN | US | 23rd Jan 2023 |
| 202.87.28.0/22 | 1k | ARIN | US | 3rd Feb 2025 |
| 203.147.144.0/20 | 4.1k | ARIN | US | 22nd May 2024 |
| 203.191.36.0/22 | 1k | ARIN | US | 11th Dec 2023 |
| 203.24.120.0/24 | 256 | ARIN | US | 9th Jun 2021 |
| 203.27.124.0/24 | 256 | ARIN | US | 23rd Feb 2026 |
| 203.27.64.0/24 | 256 | ARIN | US | 9th Aug 2021 |
| 203.28.248.0/24 | 256 | ARIN | US | 5th Jan 2021 |
| 203.31.244.0/23 | 512 | ARIN | US | 18th Nov 2024 |
| 203.62.143.0/24 | 256 | ARIN | US | 23rd Feb 2026 |
| 203.96.184.0/22 | 1k | ARIN | US | 12th Jan 2022 |
| 204.10.0.0/22 | 1k | ARIN | US | 1st Mar 2023 |
| 204.10.18.0/23 | 512 | ARIN | US | 23rd Sept 2014 |
| 204.10.189.0/24 | 256 | ARIN | US | 26th Apr 2019 |
| 204.10.40.0/22 | 1k | ARIN | US | 29th Dec 2004 |
| 204.10.96.0/21 | 2k | ARIN | US | 10th Dec 2004 |
| 204.106.24.0/21 | 2k | ARIN | US | 21st Jul 1994 |
| 204.106.64.0/18 | 16.4k | ARIN | US | 6th Feb 1995 |
| 204.107.0.0/21 | 2k | ARIN | US | 25th Jul 1994 |
| 204.107.100.0/24 | 256 | ARIN | US | 11th Oct 1994 |
| 204.107.101.0/24 | 256 | ARIN | US | 11th Oct 1994 |
| 204.107.103.0/24 | 256 | ARIN | US | 12th Oct 1994 |
| 204.107.104.0/24 | 256 | ARIN | US | 12th Oct 1994 |
| 204.107.105.0/24 | 256 | ARIN | US | 12th Oct 1994 |
| 204.107.106.0/24 | 256 | ARIN | US | 12th Oct 1994 |
| 204.107.107.0/24 | 256 | ARIN | US | 12th Oct 1994 |
| 204.107.108.0/24 | 256 | ARIN | US | 12th Oct 1994 |