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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,273 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 72.172.90.0/23 | 512 | ARIN |  US | 24th Jan 2007 |
| 72.172.92.0/22 | 1k | ARIN | US | 24th Jan 2007 |
| 72.18.92.0/22 | 1k | ARIN | US | 7th Oct 2021 |
| 72.19.4.0/22 | 1k | ARIN | US | 4th Sept 2019 |
| 72.2.112.0/20 | 4.1k | ARIN | US | 14th May 2008 |
| 72.2.160.0/20 | 4.1k | ARIN | US | 9th Feb 2006 |
| 72.2.180.0/24 | 256 | ARIN | US | 15th Jul 2016 |
| 72.2.192.0/19 | 8.2k | ARIN | US | 13th Oct 2004 |
| 72.22.100.0/22 | 1k | ARIN | US | 13th Jan 2026 |
| 72.22.69.0/24 | 256 | ARIN | US | 18th Jan 2005 |
| 72.22.70.0/23 | 512 | ARIN | US | 18th Jan 2005 |
| 72.22.84.0/23 | 512 | ARIN | US | 18th Jan 2005 |
| 72.22.87.0/24 | 256 | ARIN | US | 18th Jan 2005 |
| 72.22.96.0/22 | 1k | ARIN | US | 13th Jan 2026 |
| 72.242.0.0/15 | 131k | ARIN | US | 6th Feb 2025 |
| 72.28.77.0/24 | 256 | ARIN | US | 1st Sept 2006 |
| 72.29.144.0/20 | 4.1k | ARIN | US | 13th Nov 2007 |
| 72.34.160.0/20 | 4.1k | ARIN | US | 23rd May 2012 |
| 72.42.248.0/24 | 256 | ARIN | US | 17th Apr 2017 |
| 72.42.252.0/24 | 256 | ARIN | US | 1st May 2018 |
| 72.46.104.0/22 | 1k | ARIN | US | 24th Aug 2017 |
| 72.46.108.0/23 | 512 | ARIN | US | 9th Dec 2016 |
| 72.46.183.0/24 | 256 | ARIN | US | 24th Jun 2008 |
| 72.5.104.0/21 | 2k | ARIN | US | 30th Sept 2004 |
| 72.5.112.0/22 | 1k | ARIN | US | 30th Sept 2004 |
| 72.5.120.0/21 | 2k | ARIN | US | 30th Sept 2004 |
| 72.5.44.0/23 | 512 | ARIN | US | 30th Sept 2004 |
| 72.51.52.0/22 | 1k | ARIN | US | 4th Dec 2025 |
| 72.57.32.0/19 | 8.2k | ARIN | US | 26th Feb 2008 |
| 72.6.0.0/15 | 131k | ARIN | US | 9th Nov 2004 |
| 72.64.128.0/17 | 32.8k | ARIN | US | 24th Jun 2005 |
| 72.64.16.0/20 | 4.1k | ARIN | US | 24th Jun 2005 |
| 72.64.64.0/18 | 16.4k | ARIN | US | 24th Jun 2005 |
| 72.65.64.0/19 | 8.2k | ARIN | US | 24th Jun 2005 |
| 72.71.0.0/17 | 32.8k | ARIN | US | 24th Jun 2005 |
| 72.87.0.0/19 | 8.2k | ARIN | US | 24th Jun 2005 |
| 72.87.128.0/17 | 32.8k | ARIN | US | 24th Jun 2005 |
| 72.87.32.0/20 | 4.1k | ARIN | US | 24th Jun 2005 |
| 72.9.228.0/24 | 256 | ARIN | US | 26th Nov 2018 |
| 72.9.242.0/24 | 256 | ARIN | US | 26th Nov 2018 |
| 72.92.160.0/19 | 8.2k | ARIN | US | 24th Jun 2005 |
| 72.95.64.0/20 | 4.1k | ARIN | US | 24th Jun 2005 |
| 74.112.216.0/21 | 2k | ARIN | US | 24th Apr 2009 |
| 74.112.224.0/22 | 1k | ARIN | US | 24th Apr 2009 |
| 74.113.152.0/22 | 1k | ARIN | US | 12th May 2009 |
| 74.113.200.0/24 | 256 | ARIN | US | 12th Oct 2017 |
| 74.113.202.0/23 | 512 | ARIN | US | 20th Sept 2017 |
| 74.113.204.0/22 | 1k | ARIN | US | 18th May 2009 |
| 74.113.28.0/22 | 1k | ARIN | US | 22nd May 2012 |
| 74.113.8.0/22 | 1k | ARIN | US | 3rd Apr 2025 |