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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,392 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 205.159.66.0/24 | 256 | ARIN |  US | 15th Mar 1995 |
| 205.159.67.0/24 | 256 | ARIN | US | 16th Mar 1995 |
| 205.159.68.0/24 | 256 | ARIN | US | 16th Mar 1995 |
| 205.159.69.0/24 | 256 | ARIN | US | 16th Mar 1995 |
| 205.159.72.0/24 | 256 | ARIN | US | 7th Mar 2012 |
| 205.159.73.0/24 | 256 | ARIN | US | 16th Mar 1995 |
| 205.159.74.0/24 | 256 | ARIN | US | 16th Mar 1995 |
| 205.159.77.0/24 | 256 | ARIN | US | 16th Mar 1995 |
| 205.159.78.0/24 | 256 | ARIN | US | 16th Mar 1995 |
| 205.159.79.0/24 | 256 | AFRINIC |  ZA | 16th Mar 1995 |
| 205.159.8.0/24 | 256 | ARIN | US | 9th Mar 1995 |
| 205.159.80.0/24 | 256 | ARIN | US | 16th Mar 1995 |
| 205.159.81.0/24 | 256 | ARIN | US | 16th Mar 1995 |
| 205.159.82.0/24 | 256 | ARIN | US | 16th Mar 1995 |
| 205.159.84.0/24 | 256 | ARIN | US | 16th Mar 1995 |
| 205.159.87.0/24 | 256 | ARIN | US | 16th Mar 1995 |
| 205.159.90.0/24 | 256 | ARIN | US | 17th Mar 1995 |
| 205.159.95.0/24 | 256 | ARIN | US | 21st Mar 1995 |
| 205.159.96.0/24 | 256 | ARIN | US | 22nd Mar 1995 |
| 205.159.97.0/24 | 256 | ARIN | US | 22nd Mar 1995 |
| 205.159.98.0/24 | 256 | ARIN | US | 22nd Mar 1995 |
| 205.166.0.0/24 | 256 | ARIN | US | 17th Mar 1995 |
| 205.166.1.0/24 | 256 | ARIN | US | 17th Mar 1995 |
| 205.166.100.0/24 | 256 | ARIN | US | 29th Mar 1995 |
| 205.166.101.0/24 | 256 | ARIN | US | 29th Mar 1995 |
| 205.166.102.0/24 | 256 | ARIN | US | 29th Mar 1995 |
| 205.166.103.0/24 | 256 | ARIN | US | 29th Mar 1995 |
| 205.166.104.0/24 | 256 | ARIN | US | 29th Mar 1995 |
| 205.166.105.0/24 | 256 | ARIN | US | 29th Mar 1995 |
| 205.166.106.0/24 | 256 | ARIN | US | 29th Mar 1995 |
| 205.166.107.0/24 | 256 | ARIN | US | 29th Mar 1995 |
| 205.166.108.0/24 | 256 | ARIN | US | 3rd Apr 2025 |
| 205.166.11.0/24 | 256 | ARIN | US | 20th Mar 1995 |
| 205.166.110.0/24 | 256 | ARIN | US | 29th Mar 1995 |
| 205.166.111.0/24 | 256 | ARIN | US | 29th Mar 1995 |
| 205.166.112.0/24 | 256 | ARIN | US | 30th Mar 1995 |
| 205.166.113.0/24 | 256 | ARIN | US | 30th Mar 1995 |
| 205.166.114.0/24 | 256 | ARIN | US | 30th Mar 1995 |
| 205.166.115.0/24 | 256 | ARIN | US | 30th Mar 1995 |
| 205.166.117.0/24 | 256 | ARIN | US | 30th Mar 1995 |
| 205.166.118.0/24 | 256 | ARIN | US | 30th Mar 1995 |
| 205.166.12.0/24 | 256 | ARIN | US | 20th Mar 1995 |
| 205.166.120.0/24 | 256 | ARIN | US | 31st Mar 1995 |
| 205.166.121.0/24 | 256 | ARIN | US | 31st Mar 1995 |
| 205.166.122.0/24 | 256 | ARIN | US | 31st Mar 1995 |
| 205.166.123.0/24 | 256 | ARIN |  CA | 3rd Apr 2025 |
| 205.166.124.0/24 | 256 | ARIN | US | 31st Mar 1995 |
| 205.166.125.0/24 | 256 | ARIN | US | 31st Mar 1995 |
| 205.166.126.0/24 | 256 | ARIN | US | 31st Mar 1995 |
| 205.166.127.0/24 | 256 | ARIN | US | 3rd Apr 1995 |