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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
27,019 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 206.15.129.0/24 | 256 | ARIN |  US | 25th May 1995 |
| 206.151.48.0/20 | 4.1k | ARIN | US | 6th Oct 1995 |
| 206.153.0.0/18 | 16.4k | ARIN | US | 6th Oct 1995 |
| 206.153.128.0/17 | 32.8k | ARIN | US | 6th Oct 1995 |
| 206.153.64.0/19 | 8.2k | ARIN | US | 6th Oct 1995 |
| 206.153.96.0/19 | 8.2k | ARIN | US | 6th Oct 1995 |
| 206.154.0.0/19 | 8.2k | ARIN | US | 6th Oct 1995 |
| 206.154.128.0/17 | 32.8k | ARIN | US | 6th Oct 1995 |
| 206.154.32.0/20 | 4.1k | ARIN | US | 6th Oct 1995 |
| 206.154.48.0/21 | 2k | ARIN | US | 6th Oct 1995 |
| 206.154.56.0/21 | 2k | ARIN | US | 6th Oct 1995 |
| 206.154.64.0/18 | 16.4k | ARIN | US | 6th Oct 1995 |
| 206.166.200.0/24 | 256 | ARIN | US | 6th Dec 2019 |
| 206.166.201.0/24 | 256 | ARIN | US | 3rd Apr 2025 |
| 206.166.221.0/24 | 256 | ARIN | US | 14th Dec 2018 |
| 206.167.1.0/24 | 256 | ARIN | US | 6th Mar 2009 |
| 206.167.22.0/24 | 256 | ARIN | US | 22nd Dec 1995 |
| 206.167.48.0/24 | 256 | ARIN | US | 16th Jan 1996 |
| 206.168.115.0/24 | 256 | ARIN | US | 14th Nov 2023 |
| 206.168.143.0/24 | 256 | ARIN | US | 5th Jul 2023 |
| 206.168.192.0/24 | 256 | ARIN | US | 4th Apr 2023 |
| 206.168.221.0/24 | 256 | ARIN | US | 3rd Apr 2023 |
| 206.168.240.0/22 | 1k | ARIN | US | 3rd Apr 2023 |
| 206.168.248.0/24 | 256 | ARIN | US | 7th Apr 2023 |
| 206.174.224.0/19 | 8.2k | ARIN | US | 10th Nov 2006 |
| 206.175.0.0/16 | 65.5k | ARIN | US | 26th Oct 1995 |
| 206.183.100.0/22 | 1k | ARIN | US | 20th Nov 2008 |
| 206.183.140.0/22 | 1k | ARIN | US | 2nd Apr 2024 |
| 206.183.152.0/24 | 256 | ARIN | US | 2nd Apr 2024 |
| 206.183.158.0/24 | 256 | ARIN | US | 1st Jul 2026 |
| 206.183.159.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 206.183.160.0/21 | 2k | ARIN | US | 15th Nov 1995 |
| 206.183.32.0/19 | 8.2k | ARIN | US | 1st Nov 1995 |
| 206.188.203.0/24 | 256 | ARIN | US | 28th Apr 2021 |
| 206.190.128.0/19 | 8.2k | ARIN | US | 21st Dec 1995 |
| 206.190.160.0/19 | 8.2k | ARIN | US | 3rd Jan 1996 |
| 206.190.224.0/22 | 1k | ARIN | US | 17th Jan 1996 |
| 206.190.96.0/19 | 8.2k | ARIN | US | 21st Dec 1995 |
| 206.191.160.0/21 | 2k | ARIN | US | 1st Apr 1997 |
| 206.196.100.0/24 | 256 | ARIN | US | 31st Jul 2026 |
| 206.196.192.0/19 | 8.2k | ARIN | US | 3rd Aug 1995 |
| 206.197.0.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 206.197.10.0/24 | 256 | ARIN | US | 19th Jun 1995 |
| 206.197.100.0/24 | 256 | ARIN | US | 20th Jul 1995 |
| 206.197.101.0/24 | 256 | ARIN | US | 20th Jul 1995 |
| 206.197.102.0/24 | 256 | ARIN | US | 24th Jul 1995 |
| 206.197.104.0/24 | 256 | ARIN | US | 24th Jul 1995 |
| 206.197.105.0/24 | 256 | ARIN | US | 24th Jul 1995 |
| 206.197.106.0/24 | 256 | ARIN | US | 24th Jul 1995 |
| 206.197.107.0/24 | 256 | ARIN | US | 24th Jul 1995 |