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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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.
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Countries with the most unannounced blocks, largest first.
Unannounced blocks in United States
26,955 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 216.36.40.0/23 | 512 | ARIN |  US | 17th Aug 2006 |
| 216.36.43.0/24 | 256 | ARIN | US | 17th Aug 2006 |
| 216.36.44.0/22 | 1k | ARIN | US | 17th Aug 2006 |
| 216.38.104.0/22 | 1k | ARIN | US | 5th Jul 2006 |
| 216.38.108.0/23 | 512 | ARIN | US | 5th Jul 2006 |
| 216.38.110.0/24 | 256 | ARIN | US | 5th Jul 2006 |
| 216.38.96.0/21 | 2k | ARIN | US | 5th Jul 2006 |
| 216.39.192.0/19 | 8.2k | ARIN | US | 21st Nov 2000 |
| 216.40.192.0/18 | 16.4k | ARIN | US | 5th Oct 2000 |
| 216.40.88.0/22 | 1k | ARIN | US | 27th Dec 2024 |
| 216.41.144.0/20 | 4.1k | ARIN | US | 16th Aug 2016 |
| 216.41.225.0/24 | 256 | ARIN | US | 23rd Jan 2019 |
| 216.46.224.0/19 | 8.2k | ARIN | US | 31st Aug 1998 |
| 216.47.112.0/20 | 4.1k | ARIN | US | 6th Jun 2002 |
| 216.47.64.0/19 | 8.2k | ARIN | US | 24th Jul 2026 |
| 216.48.110.0/23 | 512 | ARIN | US | 27th Feb 2017 |
| 216.49.80.0/20 | 4.1k | ARIN | US | 5th Jun 2000 |
| 216.52.10.0/23 | 512 | ARIN | US | 24th Aug 1998 |
| 216.52.102.0/23 | 512 | ARIN | US | 24th Aug 1998 |
| 216.52.21.0/24 | 256 | ARIN | US | 20th Nov 2023 |
| 216.52.212.0/24 | 256 | ARIN | US | 10th Sept 2026 |
| 216.52.214.0/24 | 256 | ARIN | US | 7th Oct 2026 |
| 216.52.215.0/24 | 256 | ARIN | US | 24th Aug 1998 |
| 216.52.218.0/24 | 256 | ARIN | US | 7th Aug 2026 |
| 216.52.224.0/21 | 2k | ARIN | US | 24th Aug 1998 |
| 216.52.236.0/24 | 256 | ARIN | US | 8th Oct 2026 |
| 216.52.237.0/24 | 256 | ARIN | US | 26th Oct 2026 |
| 216.52.238.0/24 | 256 | ARIN | US | 24th Aug 1998 |
| 216.52.242.0/23 | 512 | ARIN | US | 24th Aug 1998 |
| 216.52.246.0/23 | 512 | ARIN | US | 24th Aug 1998 |
| 216.52.252.0/24 | 256 | ARIN | US | 6th Nov 2026 |
| 216.52.36.0/22 | 1k | ARIN | US | 24th Aug 1998 |
| 216.52.40.0/22 | 1k | ARIN | US | 24th Aug 1998 |
| 216.52.96.0/22 | 1k | ARIN | US | 24th Aug 1998 |
| 216.57.121.0/24 | 256 | ARIN | US | 12th Aug 2005 |
| 216.57.80.0/23 | 512 | ARIN | US | 14th Jul 2005 |
| 216.58.176.0/20 | 4.1k | ARIN | US | 10th Mar 2005 |
| 216.69.64.0/19 | 8.2k | ARIN | US | 23rd Oct 1998 |
| 216.7.64.0/20 | 4.1k | ARIN | US | 14th Jan 2009 |
| 216.71.240.0/20 | 4.1k | ARIN | US | 4th May 2005 |
| 216.71.96.0/22 | 1k | ARIN | US | 24th Sept 2018 |
| 216.73.148.0/22 | 1k | ARIN | US | 4th Oct 2021 |
| 216.73.187.0/24 | 256 | ARIN | US | 8th Oct 2021 |
| 216.73.191.0/24 | 256 | ARIN | US | 8th Oct 2021 |
| 216.73.220.0/22 | 1k | ARIN | US | 10th Jun 1999 |
| 216.82.240.0/20 | 4.1k | ARIN | US | 17th Sept 2003 |
| 216.83.96.0/19 | 8.2k | ARIN | US | 15th Sept 2000 |
| 216.9.162.0/24 | 256 | ARIN | US | 27th Jul 2021 |
| 216.9.163.0/24 | 256 | ARIN | US | 18th Oct 1999 |
| 216.9.32.0/20 | 4.1k | ARIN | US | 12th Oct 1999 |