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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
30,434 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 161.199.191.0/24 | 256 | ARIN |  US | 29th Jan 1993 |
| 161.199.2.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.20.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.200.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.202.0/24 | 256 | ARIN | US | 21st Jan 2021 |
| 161.199.218.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.22.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.220.0/22 | 1k | ARIN | US | 29th Jan 1993 |
| 161.199.224.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.226.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.228.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.231.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.232.0/21 | 2k | ARIN | US | 29th Jan 1993 |
| 161.199.248.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.25.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.254.0/23 | 512 | ARIN | US | 11th Dec 2019 |
| 161.199.27.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.28.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.29.0/24 | 256 | ARIN | US | 7th Aug 2020 |
| 161.199.30.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.32.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.35.0/24 | 256 | ARIN | US | 14th Oct 2025 |
| 161.199.38.0/24 | 256 | ARIN | US | 22nd Jan 2021 |
| 161.199.39.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.4.0/22 | 1k | ARIN | US | 29th Jan 1993 |
| 161.199.40.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.44.0/22 | 1k | ARIN | US | 29th Jan 1993 |
| 161.199.48.0/22 | 1k | ARIN | US | 29th Jan 1993 |
| 161.199.52.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.55.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.64.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.66.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.68.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.70.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.72.0/22 | 1k | ARIN | US | 29th Jan 1993 |
| 161.199.8.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.84.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.87.0/24 | 256 | ARIN | US | 13th Aug 2019 |
| 161.199.91.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.92.0/23 | 512 | ARIN | US | 7th Jun 2019 |
| 161.199.94.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.96.0/21 | 2k | ARIN | US | 29th Jan 1993 |
| 161.201.0.0/16 | 65.5k | ARIN | US | 29th Jan 1993 |
| 161.204.0.0/16 | 65.5k | ARIN | US | 9th Feb 1993 |
| 161.210.100.0/22 | 1k | ARIN | US | 13th Jan 2026 |
| 161.210.104.0/22 | 1k | ARIN | US | 15th May 2026 |
| 161.210.112.0/20 | 4.1k | ARIN | US | 18th Feb 1993 |
| 161.210.16.0/20 | 4.1k | ARIN | US | 18th Feb 1993 |
| 161.210.160.0/20 | 4.1k | ARIN | US | 18th Feb 1993 |
| 161.210.176.0/21 | 2k | ARIN | US | 18th Feb 1993 |