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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,124 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.150.48.0/23 | 512 | ARIN |  US | 17th Feb 2015 |
| 192.150.51.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.52.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.53.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.54.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.55.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.56.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.57.0/24 | 256 | ARIN | US | 5th Feb 2019 |
| 192.150.58.0/23 | 512 | RIPE NCC |  SE | 13th Aug 1992 |
| 192.150.6.0/24 | 256 | ARIN | US | 25th Jun 1992 |
| 192.150.60.0/22 | 1k | RIPE NCC | SE | 13th Aug 1992 |
| 192.150.64.0/22 | 1k | RIPE NCC | SE | 13th Aug 1992 |
| 192.150.68.0/23 | 512 | RIPE NCC | SE | 13th Aug 1992 |
| 192.150.7.0/24 | 256 | ARIN | US | 25th Jun 1992 |
| 192.150.70.0/24 | 256 | RIPE NCC | SE | 13th Aug 1992 |
| 192.150.72.0/24 | 256 | RIPE NCC | SE | 13th Aug 1992 |
| 192.150.73.0/24 | 256 | ARIN | US | 7th Dec 2024 |
| 192.150.76.0/24 | 256 | RIPE NCC | SE | 13th Aug 1992 |
| 192.150.78.0/24 | 256 | RIPE NCC | SE | 19th May 1994 |
| 192.150.79.0/24 | 256 | RIPE NCC | SE | 5th Mar 1992 |
| 192.150.8.0/24 | 256 | ARIN | US | 25th Jun 1992 |
| 192.150.80.0/24 | 256 | RIPE NCC | SE | 5th Mar 1992 |
| 192.150.81.0/24 | 256 | RIPE NCC | SE | 5th Mar 1992 |
| 192.150.82.0/24 | 256 | RIPE NCC | SE | 5th Mar 1992 |
| 192.150.87.0/24 | 256 | ARIN | US | 6th Mar 1992 |
| 192.150.89.0/24 | 256 | RIPE NCC |  GB | 6th Mar 1992 |
| 192.150.90.0/23 | 512 | ARIN |  CA | 6th Mar 1992 |
| 192.150.95.0/24 | 256 | ARIN | US | 6th Mar 1992 |
| 192.150.97.0/24 | 256 | ARIN | US | 6th Mar 1992 |
| 192.150.98.0/24 | 256 | ARIN | US | 6th Mar 1992 |
| 192.150.99.0/24 | 256 | ARIN | US | 6th Mar 1992 |
| 192.151.0.0/24 | 256 | ARIN | US | 5th Jun 2015 |
| 192.151.1.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.10.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.100.0/24 | 256 | ARIN | US | 11th Mar 1994 |
| 192.151.101.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.102.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.103.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.104.0/22 | 1k | ARIN | US | 26th Mar 1992 |
| 192.151.108.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.11.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.111.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.112.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.113.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.114.0/23 | 512 | ARIN | US | 26th Mar 1992 |
| 192.151.116.0/23 | 512 | ARIN | US | 26th Mar 1992 |
| 192.151.118.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.119.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.12.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.120.0/24 | 256 | ARIN | US | 26th Mar 1992 |