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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,972 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 174.34.255.0/24 | 256 | ARIN |  US | 18th Apr 2019 |
| 174.8.0.0/13 | 524k | ARIN | US | 7th Jan 2009 |
| 176.10.89.0/24 | 256 | RIPE NCC | US | 23rd Jan 2025 |
| 176.117.111.0/24 | 256 | RIPE NCC | US | 24th Jul 2025 |
| 176.126.97.0/24 | 256 | RIPE NCC | US | 27th Jan 2026 |
| 178.249.104.0/21 | 2k | RIPE NCC | US | 25th May 2010 |
| 178.255.244.0/22 | 1k | RIPE NCC | US | 15th Jul 2010 |
| 178.79.192.0/18 | 16.4k | RIPE NCC | US | 12th May 2010 |
| 179.197.0.0/18 | 16.4k | ARIN | US | 20th Feb 2025 |
| 184.128.0.0/12 | 1M | ARIN | US | 25th Feb 2010 |
| 184.170.144.0/20 | 4.1k | ARIN | US | 18th May 2011 |
| 184.172.0.0/15 | 131k | ARIN | US | 6th Oct 2010 |
| 184.88.0.0/14 | 262k | ARIN | US | 31st Mar 2010 |
| 184.95.16.0/20 | 4.1k | ARIN | US | 14th Aug 2024 |
| 185.1.180.0/24 | 256 | RIPE NCC | US | 6th Jul 2020 |
| 185.116.100.0/22 | 1k | RIPE NCC | US | 8th Sept 2015 |
| 185.116.233.0/24 | 256 | RIPE NCC | US | 10th Sept 2015 |
| 185.12.232.0/22 | 1k | RIPE NCC | US | 11th Dec 2012 |
| 185.133.148.0/22 | 1k | RIPE NCC | US | 5th Jan 2016 |
| 185.133.252.0/22 | 1k | RIPE NCC | US | 11th Jan 2016 |
| 185.135.152.0/22 | 1k | RIPE NCC | US | 22nd Jan 2016 |
| 185.138.192.0/22 | 1k | RIPE NCC | US | 15th Feb 2016 |
| 185.142.4.0/22 | 1k | RIPE NCC | US | 4th Mar 2016 |
| 185.144.68.0/23 | 512 | ARIN | US | 19th Sept 2024 |
| 185.147.152.0/22 | 1k | RIPE NCC | US | 15th Apr 2016 |
| 185.148.48.0/22 | 1k | RIPE NCC | US | 19th Apr 2016 |
| 185.154.244.0/22 | 1k | RIPE NCC | US | 6th Jun 2016 |
| 185.158.244.0/22 | 1k | RIPE NCC | US | 8th Jul 2016 |
| 185.161.104.0/22 | 1k | RIPE NCC | US | 28th Jul 2016 |
| 185.164.168.0/22 | 1k | RIPE NCC | US | 22nd Aug 2016 |
| 185.175.68.0/22 | 1k | RIPE NCC | US | 27th Oct 2016 |
| 185.178.52.0/22 | 1k | RIPE NCC | US | 18th Nov 2016 |
| 185.179.204.0/22 | 1k | RIPE NCC | US | 30th Nov 2016 |
| 185.183.244.0/22 | 1k | RIPE NCC | US | 30th Dec 2016 |
| 185.2.136.0/22 | 1k | RIPE NCC | US | 18th Sept 2012 |
| 185.20.220.0/22 | 1k | ARIN | US | 11th May 2017 |
| 185.203.192.0/22 | 1k | RIPE NCC | US | 15th May 2017 |
| 185.203.207.0/24 | 256 | ARIN | US | 11th Apr 2022 |
| 185.205.100.0/22 | 1k | RIPE NCC | US | 24th May 2017 |
| 185.212.144.0/22 | 1k | RIPE NCC | US | 12th Jul 2017 |
| 185.215.48.0/22 | 1k | RIPE NCC | US | 27th Jul 2017 |
| 185.220.140.0/22 | 1k | RIPE NCC | US | 13th Sept 2017 |
| 185.235.180.0/22 | 1k | RIPE NCC | US | 6th Dec 2017 |
| 185.242.219.0/24 | 256 | RIPE NCC | US | 20th Jan 2020 |
| 185.249.221.0/24 | 256 | RIPE NCC | US | 15th Mar 2018 |
| 185.253.1.0/24 | 256 | RIPE NCC | US | 10th Sept 2021 |
| 185.253.5.0/24 | 256 | RIPE NCC | US | 10th Sept 2021 |
| 185.32.192.0/22 | 1k | RIPE NCC | US | 8th Aug 2013 |
| 185.33.220.0/22 | 1k | RIPE NCC | US | 23rd Aug 2013 |
| 185.39.52.0/22 | 1k | ARIN | US | 22nd Jun 2020 |