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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 the most unannounced blocks, largest first.
Unannounced blocks in United States
26,993 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 179.253.128.0/18 | 16.4k | RIPE NCC |  US | 6th Mar 2025 |
| 179.253.64.0/18 | 16.4k | RIPE NCC | US | 6th Mar 2025 |
| 179.254.128.0/18 | 16.4k | RIPE NCC | US | 6th Mar 2025 |
| 179.254.224.0/20 | 4.1k | ARIN | US | 13th Mar 2025 |
| 179.255.192.0/20 | 4.1k | ARIN | US | 13th Mar 2025 |
| 179.255.80.0/20 | 4.1k | ARIN | US | 13th Mar 2025 |
| 179.67.0.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 179.67.128.0/18 | 16.4k | RIPE NCC | US | 20th Feb 2025 |
| 179.69.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 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 |
| 185.125.142.0/24 | 256 | RIPE NCC | US | 22nd Jan 2026 |
| 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 |
| 185.159.89.0/24 | 256 | ARIN | US | 13th Oct 2025 |
| 185.161.104.0/22 | 1k | RIPE NCC | US | 28th Jul 2016 |
| 185.164.168.0/22 | 1k | RIPE NCC | US | 22nd Aug 2016 |
| 185.167.182.0/24 | 256 | ARIN | US | 9th Jun 2022 |
| 185.175.68.0/22 | 1k | RIPE NCC | US | 27th Oct 2016 |
| 185.176.52.0/22 | 1k | ARIN | US | 19th Feb 2019 |
| 185.178.52.0/22 | 1k | RIPE NCC | US | 18th Nov 2016 |
| 185.179.204.0/22 | 1k | RIPE NCC | US | 30th Nov 2016 |
| 185.2.136.0/22 | 1k | RIPE NCC | US | 18th Sept 2012 |
| 185.20.220.0/22 | 1k | ARIN | US | 11th 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 |
| 185.239.172.0/24 | 256 | RIPE NCC | US | 4th Jan 2018 |
| 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 |