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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
84,619 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 66.249.172.0/22 | 1k | ARIN |  US | 13th Feb 2012 |
| 66.252.240.0/20 | 4.1k | ARIN | US | 27th Mar 2006 |
| 66.255.192.0/21 | 2k | ARIN | US | 9th Feb 2004 |
| 66.255.200.0/22 | 1k | RIPE NCC |  IE | 9th Feb 2004 |
| 66.33.64.0/24 | 256 | ARIN | US | 29th Nov 2022 |
| 66.33.7.0/24 | 256 | ARIN |  CA | 13th Oct 2000 |
| 66.33.76.0/24 | 256 | ARIN | US | 2nd May 2024 |
| 66.33.95.0/24 | 256 | ARIN | US | 24th Jun 2024 |
| 66.36.128.0/19 | 8.2k | ARIN | CA | 22nd Aug 2002 |
| 66.36.64.0/19 | 8.2k | ARIN | US | 15th Aug 2002 |
| 66.37.0.0/19 | 8.2k | ARIN | US | 20th Oct 2000 |
| 66.37.112.0/20 | 4.1k | ARIN | US | 17th Feb 2004 |
| 66.40.108.0/22 | 1k | ARIN | US | 25th Mar 2025 |
| 66.40.192.0/18 | 16.4k | ARIN | CA | 31st Oct 2000 |
| 66.40.64.0/19 | 8.2k | ARIN | CA | 31st Oct 2000 |
| 66.40.96.0/21 | 2k | ARIN | CA | 31st Oct 2000 |
| 66.45.120.0/21 | 2k | RIPE NCC |  ES | 15th Nov 2000 |
| 66.45.14.0/24 | 256 | ARIN | US | 25th Oct 2023 |
| 66.45.95.0/24 | 256 | ARIN | US | 13th May 2024 |
| 66.51.196.0/23 | 512 | ARIN | US | 5th Jan 2024 |
| 66.51.198.0/23 | 512 | ARIN | US | 27th May 2020 |
| 66.51.200.0/21 | 2k | ARIN | US | 27th May 2020 |
| 66.51.48.0/20 | 4.1k | ARIN | US | 10th Feb 2004 |
| 66.55.96.0/20 | 4.1k | ARIN | US | 15th Oct 2014 |
| 66.56.64.0/20 | 4.1k | ARIN | US | 21st Mar 2025 |
| 66.59.128.0/18 | 16.4k | ARIN | CA | 5th Jan 2001 |
| 66.59.195.0/24 | 256 | ARIN | US | 6th Jan 2022 |
| 66.59.212.0/22 | 1k | ARIN | US | 1st Apr 2024 |
| 66.59.222.0/23 | 512 | ARIN | US | 11th Jan 2022 |
| 66.6.48.0/22 | 1k | ARIN | US | 27th Dec 2023 |
| 66.6.60.0/22 | 1k | ARIN | CA | 21st Dec 2023 |
| 66.6.80.0/20 | 4.1k | ARIN | US | 22nd Nov 2000 |
| 66.63.128.0/19 | 8.2k | ARIN | US | 16th May 2002 |
| 66.63.32.0/19 | 8.2k | ARIN | US | 12th Oct 2026 |
| 66.71.196.0/23 | 512 | ARIN |  JM | 21st Feb 2025 |
| 66.71.198.0/24 | 256 | ARIN | US | 9th Jan 2026 |
| 66.71.199.0/24 | 256 | ARIN | US | 21st Nov 2025 |
| 66.79.192.0/20 | 4.1k | ARIN | US | 2nd Sept 2026 |
| 66.79.208.0/21 | 2k | ARIN | US | 18th Sept 2026 |
| 66.79.216.0/21 | 2k | ARIN | US | 28th Oct 2003 |
| 66.81.0.0/23 | 512 | ARIN | US | 28th Feb 2001 |
| 66.81.103.0/24 | 256 | ARIN | US | 13th Feb 2012 |
| 66.81.104.0/23 | 512 | ARIN | US | 13th Feb 2012 |
| 66.81.120.0/22 | 1k | ARIN | US | 13th Feb 2012 |
| 66.81.132.0/24 | 256 | ARIN | US | 13th Feb 2012 |
| 66.81.14.0/24 | 256 | ARIN | US | 13th Feb 2012 |
| 66.81.15.0/24 | 256 | ARIN | US | 13th Feb 2012 |
| 66.81.159.0/24 | 256 | ARIN | US | 13th Feb 2012 |
| 66.81.32.0/22 | 1k | ARIN | US | 13th Feb 2012 |
| 66.81.40.0/21 | 2k | ARIN | US | 13th Feb 2012 |