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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
84,619 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 66.207.56.0/22 | 1k | ARIN |  US | 15th Mar 2006 |
| 66.209.0.0/19 | 8.2k | ARIN | US | 21st Dec 2001 |
| 66.209.144.0/20 | 4.1k | ARIN | US | 4th Mar 2003 |
| 66.211.172.0/22 | 1k | ARIN | US | 25th Jan 2006 |
| 66.212.48.0/23 | 512 | ARIN | US | 27th Mar 2017 |
| 66.220.32.0/22 | 1k | ARIN | US | 18th Jan 2002 |
| 66.220.36.0/24 | 256 | ARIN | US | 18th Jan 2002 |
| 66.220.39.0/24 | 256 | ARIN | US | 24th Feb 2022 |
| 66.220.40.0/23 | 512 | ARIN | US | 18th Jan 2002 |
| 66.220.44.0/23 | 512 | ARIN | US | 18th Jan 2002 |
| 66.220.52.0/23 | 512 | ARIN | US | 17th Jan 2025 |
| 66.220.54.0/24 | 256 | ARIN | US | 17th Mar 2022 |
| 66.220.55.0/24 | 256 | ARIN | US | 16th Mar 2022 |
| 66.220.62.0/23 | 512 | ARIN | US | 18th Jan 2002 |
| 66.223.0.0/21 | 2k | ARIN | US | 23rd Feb 2024 |
| 66.223.12.0/22 | 1k | ARIN | US | 23rd Feb 2024 |
| 66.223.48.0/24 | 256 | ARIN |  CA | 25th Jan 2002 |
| 66.223.8.0/23 | 512 | ARIN | US | 23rd Feb 2024 |
| 66.223.80.0/21 | 2k | ARIN | US | 23rd Feb 2024 |
| 66.223.88.0/22 | 1k | ARIN | US | 23rd Feb 2024 |
| 66.223.92.0/23 | 512 | ARIN | US | 23rd Feb 2024 |
| 66.228.160.0/19 | 8.2k | ARIN | US | 7th Feb 2002 |
| 66.228.92.0/22 | 1k | ARIN | US | 30th Jun 2026 |
| 66.23.240.0/20 | 4.1k | ARIN | US | 17th Oct 2007 |
| 66.230.128.0/18 | 16.4k | ARIN | US | 15th Feb 2002 |
| 66.233.0.0/16 | 65.5k | ARIN | US | 28th Feb 2006 |
| 66.234.10.0/23 | 512 | RIPE NCC | US | 20th Feb 2002 |
| 66.234.12.0/23 | 512 | RIPE NCC | US | 20th Feb 2002 |
| 66.234.128.0/20 | 4.1k | RIPE NCC |  IE | 26th Feb 2002 |
| 66.234.15.0/24 | 256 | ARIN | US | 2nd May 2024 |
| 66.234.2.0/23 | 512 | ARIN | US | 26th Aug 2024 |
| 66.235.192.0/23 | 512 | ARIN | US | 7th Jul 2003 |
| 66.235.195.0/24 | 256 | ARIN | US | 7th Jul 2003 |
| 66.235.196.0/22 | 1k | ARIN | US | 7th Jul 2003 |
| 66.235.202.0/23 | 512 | ARIN | US | 7th Jul 2003 |
| 66.235.204.0/23 | 512 | ARIN | US | 7th Jul 2003 |
| 66.235.206.0/24 | 256 | ARIN | US | 7th Jul 2003 |
| 66.235.208.0/24 | 256 | ARIN | US | 7th Jul 2003 |
| 66.235.210.0/23 | 512 | ARIN | US | 7th Jul 2003 |
| 66.235.212.0/23 | 512 | ARIN | US | 7th Jul 2003 |
| 66.235.216.0/21 | 2k | ARIN | US | 7th Jul 2003 |
| 66.235.224.0/19 | 8.2k | ARIN | US | 8th Jul 2003 |
| 66.242.48.0/23 | 512 | RIPE NCC |  GB | 4th Mar 2002 |
| 66.245.180.0/22 | 1k | ARIN | US | 2nd Mar 2004 |
| 66.248.236.0/24 | 256 | ARIN | US | 26th Dec 2019 |
| 66.248.237.0/24 | 256 | ARIN | GB | 19th Dec 2019 |
| 66.248.239.0/24 | 256 | ARIN | US | 19th Dec 2019 |
| 66.248.244.0/24 | 256 | ARIN | US | 18th Dec 2019 |
| 66.248.245.0/24 | 256 | ARIN | US | 26th Dec 2019 |
| 66.249.125.0/24 | 256 | ARIN | US | 2nd Apr 2008 |