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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,458 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 204.144.77.0/24 | 256 | ARIN |  US | 4th Jan 1995 |
| 204.144.78.0/24 | 256 | ARIN |  PR | 4th Jan 1995 |
| 204.144.79.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.80.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.82.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.83.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.85.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.86.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.87.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.88.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.89.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.90.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.91.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.92.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.93.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.94.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.95.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.98.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.144.99.0/24 | 256 | ARIN | US | 4th Jan 1995 |
| 204.145.1.0/24 | 256 | ARIN | US | 15th Sept 1994 |
| 204.145.119.0/24 | 256 | ARIN | US | 20th Jan 1995 |
| 204.145.120.0/21 | 2k | ARIN | US | 13th Feb 2009 |
| 204.145.136.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.137.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.138.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.139.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.140.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.141.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.142.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.143.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.144.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.145.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.146.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.148.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.149.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.150.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.151.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.153.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.154.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.155.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.156.0/24 | 256 | ARIN | US | 9th Jan 1995 |
| 204.145.159.0/24 | 256 | ARIN | US | 11th Jan 1995 |
| 204.145.16.0/20 | 4.1k | ARIN | US | 15th Sept 1994 |
| 204.145.160.0/24 | 256 | ARIN | US | 11th Jan 1995 |
| 204.145.161.0/24 | 256 | ARIN | US | 11th Jan 1995 |
| 204.145.162.0/24 | 256 | ARIN | US | 11th Jan 1995 |
| 204.145.163.0/24 | 256 | ARIN | US | 11th Jan 1995 |
| 204.145.164.0/24 | 256 | ARIN | US | 18th Jan 1995 |
| 204.145.165.0/24 | 256 | ARIN | US | 12th Jan 1995 |
| 204.145.166.0/24 | 256 | ARIN | US | 12th Jan 1995 |