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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
27,014 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 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 |
| 216.150.24.0/22 | 1k | RIPE NCC | US | 14th Jul 1999 |
| 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 |
| 216.16.144.0/20 | 4.1k | ARIN | US | 3rd Aug 2010 |
| 216.162.192.0/22 | 1k | ARIN | US | 11th Aug 1999 |
| 216.162.196.0/23 | 512 | ARIN | US | 11th Aug 1999 |
| 216.162.208.0/22 | 1k | ARIN | US | 19th Jan 2024 |
| 216.162.32.0/21 | 2k | ARIN | US | 17th Feb 2016 |
| 216.163.224.0/20 | 4.1k | ARIN | US | 29th Jul 1999 |
| 216.169.153.0/24 | 256 | ARIN | US | 13th Feb 2020 |
| 216.169.192.0/20 | 4.1k | ARIN | US | 28th Jan 1999 |
| 216.17.96.0/20 | 4.1k | ARIN | US | 9th Jan 2003 |
| 216.170.96.0/22 | 1k | ARIN | US | 8th Apr 2022 |
| 216.171.160.0/20 | 4.1k | ARIN | US | 8th Dec 2000 |
| 216.177.144.0/21 | 2k | ARIN | US | 18th Aug 2009 |
| 216.177.158.0/23 | 512 | ARIN | US | 18th Aug 2009 |
| 216.178.112.0/20 | 4.1k | ARIN | US | 16th Aug 2000 |
| 216.178.128.0/17 | 32.8k | ARIN | US | 4th Jan 1999 |
| 216.178.32.0/20 | 4.1k | ARIN | US | 22nd May 2006 |
| 216.180.114.0/24 | 256 | ARIN | US | 10th Dec 2018 |
| 216.180.248.0/24 | 256 | ARIN | US | 26th Nov 2018 |
| 216.180.249.0/24 | 256 | ARIN | US | 19th Jun 2002 |
| 216.180.32.0/19 | 8.2k | ARIN | US | 27th Nov 2018 |
| 216.182.0.0/18 | 16.4k | ARIN | US | 28th Feb 2001 |
| 216.182.64.0/20 | 4.1k | ARIN | US | 12th Dec 2000 |
| 216.183.96.0/22 | 1k | ARIN | US | 25th Aug 2000 |
| 216.184.48.0/20 | 4.1k | ARIN | US | 14th Mar 2005 |
| 216.19.128.0/19 | 8.2k | ARIN | US | 30th May 2000 |