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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 192.150.191.0/24 | 256 | ARIN |  US | 18th Mar 1992 |
| 192.150.192.0/24 | 256 | RIPE NCC |  PT | 18th Mar 1992 |
| 192.150.193.0/24 | 256 | RIPE NCC | PT | 18th Mar 1992 |
| 192.150.197.0/24 | 256 | RIPE NCC |  NO | 18th Mar 1992 |
| 192.150.198.0/24 | 256 | RIPE NCC |  GB | 18th Mar 1992 |
| 192.150.199.0/24 | 256 | ARIN | US | 18th Mar 1992 |
| 192.150.2.0/24 | 256 | ARIN | US | 25th Jun 1992 |
| 192.150.20.0/24 | 256 | RIPE NCC |  IE | 25th Jun 1992 |
| 192.150.202.0/24 | 256 | APNIC |  AU | 18th Mar 1992 |
| 192.150.203.0/24 | 256 | RIPE NCC |  AT | 19th Mar 1992 |
| 192.150.205.0/24 | 256 | RIPE NCC |  RU | 19th Mar 1992 |
| 192.150.206.0/24 | 256 | ARIN | US | 19th Mar 1992 |
| 192.150.208.0/24 | 256 | RIPE NCC | GB | 19th Mar 1992 |
| 192.150.209.0/24 | 256 | RIPE NCC | NO | 19th Mar 1992 |
| 192.150.21.0/24 | 256 | ARIN | US | 25th Jun 1992 |
| 192.150.212.0/24 | 256 | ARIN | US | 19th Mar 1992 |
| 192.150.218.0/23 | 512 | APNIC |  NZ | 20th Mar 1992 |
| 192.150.223.0/24 | 256 | RIPE NCC | NO | 20th Mar 1992 |
| 192.150.225.0/24 | 256 | ARIN | US | 20th Mar 1992 |
| 192.150.226.0/24 | 256 | ARIN | US | 20th Mar 1992 |
| 192.150.227.0/24 | 256 | RIPE NCC | GB | 20th Mar 1992 |
| 192.150.228.0/24 | 256 | RIPE NCC | GB | 20th Mar 1992 |
| 192.150.229.0/24 | 256 | RIPE NCC | GB | 20th Mar 1992 |
| 192.150.230.0/24 | 256 | RIPE NCC | GB | 20th Mar 1992 |
| 192.150.231.0/24 | 256 | RIPE NCC | GB | 20th Mar 1992 |
| 192.150.232.0/24 | 256 | RIPE NCC | GB | 20th Mar 1992 |
| 192.150.233.0/24 | 256 | RIPE NCC | GB | 20th Mar 1992 |
| 192.150.234.0/23 | 512 | APNIC | AU | 20th Mar 1992 |
| 192.150.236.0/23 | 512 | APNIC | AU | 20th Mar 1992 |
| 192.150.238.0/24 | 256 | RIPE NCC |  HU | 23rd Mar 1992 |
| 192.150.239.0/24 | 256 | ARIN | US | 23rd Mar 1992 |
| 192.150.24.0/24 | 256 | ARIN | US | 25th Jun 1992 |
| 192.150.240.0/24 | 256 | ARIN | US | 23rd Mar 1992 |
| 192.150.241.0/24 | 256 | ARIN | US | 23rd Mar 1992 |
| 192.150.245.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.150.247.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.150.248.0/24 | 256 | RIPE NCC | GB | 26th Mar 1992 |
| 192.150.25.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.254.0/24 | 256 | RIPE NCC | NO | 27th Mar 1992 |
| 192.150.255.0/24 | 256 | ARIN | US | 22nd Jun 2015 |
| 192.150.26.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.27.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.29.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.3.0/24 | 256 | ARIN | US | 25th Jun 1992 |
| 192.150.30.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.31.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.4.0/24 | 256 | ARIN | US | 25th Jun 1992 |
| 192.150.40.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.45.0/24 | 256 | ARIN | US | 5th Mar 1992 |
| 192.150.46.0/24 | 256 | ARIN | US | 10th Sept 2019 |