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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,295 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 216.105.240.0/20 | 4.1k | ARIN |  US | 6th Aug 2003 |
| 216.109.112.0/20 | 4.1k | ARIN | US | 28th Sept 2000 |
| 216.109.188.0/22 | 1k | ARIN | US | 13th Jan 2026 |
| 216.109.96.0/20 | 4.1k | ARIN | US | 27th Sept 2000 |
| 216.115.189.0/24 | 256 | ARIN | US | 30th Aug 2019 |
| 216.115.32.0/19 | 8.2k | ARIN | US | 9th Nov 1998 |
| 216.116.48.0/20 | 4.1k | ARIN | US | 24th Jan 2001 |
| 216.117.217.0/24 | 256 | ARIN | US | 6th Oct 2017 |
| 216.117.218.0/23 | 512 | ARIN | US | 6th Oct 2017 |
| 216.117.250.0/23 | 512 | ARIN | US | 27th Sept 2005 |
| 216.117.26.0/24 | 256 | ARIN | US | 23rd Feb 2000 |
| 216.117.32.0/24 | 256 | ARIN | US | 23rd Feb 2000 |
| 216.117.50.0/23 | 512 | ARIN | US | 23rd Feb 2000 |
| 216.120.146.0/23 | 512 | ARIN | US | 30th Mar 2021 |
| 216.120.148.0/22 | 1k | ARIN | US | 2nd Apr 2021 |
| 216.120.164.0/24 | 256 | ARIN | US | 30th Apr 2021 |
| 216.120.186.0/24 | 256 | ARIN | US | 30th Apr 2021 |
| 216.122.64.0/19 | 8.2k | ARIN | US | 7th Sept 2021 |
| 216.126.48.0/21 | 2k | ARIN | US | 5th Feb 2001 |
| 216.127.96.0/20 | 4.1k | ARIN | US | 3rd Nov 1999 |
| 216.128.112.0/20 | 4.1k | ARIN | US | 9th Sept 2003 |
| 216.129.128.0/20 | 4.1k | ARIN | US | 20th Nov 1998 |
| 216.131.128.0/17 | 32.8k | ARIN | US | 24th Nov 1998 |
| 216.133.252.0/23 | 512 | ARIN | US | 18th Nov 1998 |
| 216.133.254.0/24 | 256 | ARIN | US | 18th Nov 1998 |
| 216.137.128.0/20 | 4.1k | ARIN | US | 29th Jun 2006 |
| 216.137.144.0/20 | 4.1k | ARIN | US | 9th Aug 2001 |
| 216.144.0.0/18 | 16.4k | ARIN | US | 10th Jun 2014 |
| 216.144.192.0/19 | 8.2k | ARIN | US | 31st Jul 2000 |
| 216.145.146.0/24 | 256 | ARIN | US | 9th Jun 2006 |
| 216.145.40.0/23 | 512 | ARIN | US | 1st Aug 2000 |
| 216.145.42.0/24 | 256 | ARIN | US | 1st Aug 2000 |
| 216.145.48.0/20 | 4.1k | ARIN | US | 9th Aug 2000 |
| 216.146.144.0/20 | 4.1k | ARIN | US | 4th Jun 2008 |
| 216.151.160.0/24 | 256 | ARIN | US | 20th Jul 2006 |
| 216.151.161.0/24 | 256 | ARIN | US | 23rd Dec 2024 |
| 216.151.166.0/24 | 256 | ARIN | US | 26th Dec 2024 |
| 216.151.168.0/23 | 512 | ARIN | US | 20th Jul 2006 |
| 216.151.170.0/23 | 512 | ARIN | US | 20th Dec 2024 |
| 216.151.175.0/24 | 256 | ARIN | US | 23rd Dec 2024 |
| 216.151.33.0/24 | 256 | ARIN | US | 15th Jan 2019 |
| 216.151.36.0/24 | 256 | ARIN | US | 12th Mar 2010 |
| 216.151.40.0/24 | 256 | ARIN | US | 15th Jan 2019 |
| 216.151.41.0/24 | 256 | ARIN | US | 12th Mar 2010 |
| 216.152.72.0/22 | 1k | ARIN | US | 26th Jun 2026 |
| 216.153.24.0/22 | 1k | ARIN | US | 15th Sept 2023 |
| 216.155.160.0/20 | 4.1k | ARIN | US | 6th Nov 2000 |
| 216.157.156.0/24 | 256 | ARIN | US | 23rd Dec 2020 |
| 216.157.160.0/19 | 8.2k | ARIN | US | 9th Aug 2002 |
| 216.158.176.0/20 | 4.1k | ARIN | US | 10th May 2005 |