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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 in United States
27,034 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 201.51.128.0/17 | 32.8k | ARIN |  US | 29th Jul 2026 |
| 201.58.128.0/18 | 16.4k | RIPE NCC | US | 6th Mar 2025 |
| 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 |
| 201.8.64.0/18 | 16.4k | RIPE NCC | US | 6th 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 |
| 202.0.192.0/18 | 16.4k | APNIC | US | 19th Sept 1994 |
| 202.27.250.0/24 | 256 | ARIN | US | 23rd Jan 2023 |
| 202.4.164.0/24 | 256 | APNIC | US | 24th Sept 2009 |
| 202.43.91.0/24 | 256 | APNIC | US | 17th Aug 2016 |
| 202.74.55.0/24 | 256 | APNIC | US | 17th Aug 2016 |
| 202.81.16.0/20 | 4.1k | APNIC | US | 9th Jul 2010 |
| 202.86.4.0/22 | 1k | APNIC | US | 14th Mar 2006 |
| 202.87.28.0/22 | 1k | ARIN | US | 3rd Feb 2025 |
| 203.11.96.0/24 | 256 | APNIC | US | 12th Jan 1995 |
| 203.142.11.0/24 | 256 | APNIC | US | 12th May 2004 |
| 203.147.144.0/20 | 4.1k | ARIN | US | 22nd May 2024 |
| 203.184.64.0/20 | 4.1k | APNIC | US | 6th Mar 2001 |
| 203.191.36.0/22 | 1k | ARIN | US | 11th Dec 2023 |
| 203.217.137.0/24 | 256 | APNIC | US | 23rd Jun 2009 |
| 203.24.120.0/24 | 256 | ARIN | US | 9th Jun 2021 |
| 203.25.162.0/24 | 256 | APNIC | US | 25th Mar 1996 |
| 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 |
| 203.32.0.0/22 | 1k | APNIC | US | 26th Sept 1996 |
| 203.34.210.0/24 | 256 | APNIC | US | 21st Nov 1996 |
| 203.5.14.0/23 | 512 | APNIC | US | 6th May 1994 |
| 203.6.130.0/24 | 256 | APNIC | US | 11th Jul 1994 |
| 203.62.143.0/24 | 256 | ARIN | US | 23rd Feb 2026 |
| 203.81.192.0/20 | 4.1k | RIPE NCC | US | 10th Jul 2001 |
| 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 |