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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,041 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 161.199.148.0/22 | 1k | ARIN |  US | 29th Jan 1993 |
| 161.199.15.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.154.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.157.0/24 | 256 | ARIN | US | 3rd Apr 2025 |
| 161.199.158.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.17.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.173.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.174.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.175.0/24 | 256 | ARIN |  BS | 18th Sept 2019 |
| 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 |