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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
Browse by country
Countries with unannounced space registered through ARIN, largest first.
Unannounced blocks registered through ARIN
30,384 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 104.251.192.0/20 | 4.1k | ARIN |  US | 29th Dec 2014 |
| 104.254.112.0/21 | 2k | ARIN | US | 2nd Jan 2015 |
| 104.254.132.0/22 | 1k | ARIN | US | 23rd Jan 2015 |
| 104.254.24.0/21 | 2k | ARIN | US | 23rd Dec 2014 |
| 104.254.96.0/23 | 512 | ARIN |  VG | 31st Dec 2014 |
| 104.255.120.0/22 | 1k | ARIN | US | 28th Jan 2015 |
| 104.255.136.0/22 | 1k | ARIN | US | 28th Sept 2016 |
| 104.255.216.0/22 | 1k | ARIN | US | 4th Feb 2015 |
| 104.255.34.0/24 | 256 | ARIN | US | 22nd Aug 2018 |
| 104.36.144.0/22 | 1k | ARIN | US | 3rd Jun 2014 |
| 104.36.204.0/22 | 1k | ARIN | US | 6th Jun 2014 |
| 104.36.51.0/24 | 256 | ARIN | US | 28th Mar 2025 |
| 104.37.116.0/22 | 1k | ARIN | US | 23rd Jun 2014 |
| 104.37.168.0/22 | 1k | ARIN | US | 18th Jun 2014 |
| 104.37.240.0/22 | 1k | ARIN |  CA | 7th Jul 2014 |
| 104.37.48.0/22 | 1k | ARIN | US | 25th Apr 2024 |
| 104.37.8.0/21 | 2k | ARIN | US | 9th Apr 2025 |
| 107.150.136.0/23 | 512 | ARIN | US | 13th Dec 2013 |
| 107.152.16.0/20 | 4.1k | ARIN | US | 27th Nov 2013 |
| 107.155.160.0/20 | 4.1k | ARIN | US | 13th Oct 2022 |
| 107.161.152.0/24 | 256 | ARIN | CA | 17th Sept 2018 |
| 107.161.153.0/24 | 256 | ARIN | US | 23rd Sept 2020 |
| 107.161.33.0/24 | 256 | ARIN | CA | 9th Jan 2014 |
| 107.161.48.0/24 | 256 | ARIN | US | 13th Jan 2014 |
| 107.161.49.0/24 | 256 | ARIN | US | 6th Oct 2022 |
| 107.164.0.0/15 | 131k | ARIN | US | 21st Jun 2024 |
| 107.167.240.0/24 | 256 | ARIN | US | 23rd Dec 2024 |
| 107.167.244.0/22 | 1k | ARIN | US | 4th Feb 2014 |
| 107.176.0.0/15 | 131k | ARIN | US | 9th Mar 2020 |
| 107.182.137.0/24 | 256 | ARIN | US | 7th Apr 2021 |
| 107.182.48.0/20 | 4.1k | ARIN | US | 7th Feb 2014 |
| 107.184.0.0/15 | 131k | ARIN | US | 12th Feb 2014 |
| 107.190.160.0/20 | 4.1k | ARIN | US | 17th Apr 2014 |
| 107.191.240.0/20 | 4.1k | ARIN | US | 31st Dec 2018 |
| 107.191.64.0/23 | 512 | ARIN | US | 30th Apr 2019 |
| 107.191.69.0/24 | 256 | ARIN | US | 8th Apr 2019 |
| 107.191.70.0/23 | 512 | ARIN | US | 25th Mar 2019 |
| 107.191.75.0/24 | 256 | ARIN | US | 28th Mar 2018 |
| 107.6.64.0/21 | 2k | ARIN | US | 23rd Jul 2026 |
| 108.160.212.0/22 | 1k | ARIN | US | 5th Jan 2022 |
| 108.160.220.0/22 | 1k | ARIN | US | 13th Jan 2026 |
| 108.161.16.0/20 | 4.1k | ARIN | US | 19th Oct 2011 |
| 108.161.240.0/20 | 4.1k | ARIN | US | 11th Nov 2011 |
| 108.171.224.0/20 | 4.1k | ARIN | US | 5th Mar 2012 |
| 108.174.88.0/22 | 1k | ARIN | US | 18th Jun 2018 |
| 108.174.92.0/22 | 1k | ARIN | US | 25th Jul 2018 |
| 108.175.128.0/20 | 4.1k | ARIN | CA | 27th Feb 2012 |
| 108.182.0.0/15 | 131k | ARIN | US | 30th Aug 2012 |
| 108.184.0.0/15 | 131k | ARIN | US | 24th Jan 2013 |
| 109.233.32.0/21 | 2k | ARIN | US | 13th Dec 2022 |