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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 204.238.225.0/24 | 256 | ARIN |  US | 8th Jun 1995 |
| 204.238.226.0/24 | 256 | ARIN | US | 8th Jun 1995 |
| 204.238.227.0/24 | 256 | ARIN | US | 9th Jun 1995 |
| 204.238.228.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.229.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.23.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.230.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.231.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.233.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.235.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.238.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.239.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.240.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.241.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.242.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.243.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.244.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.246.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.247.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.248.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.249.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.251.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.253.0/24 | 256 | ARIN | US | 13th Jun 1995 |
| 204.238.27.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.28.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.29.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.3.0/24 | 256 | ARIN | US | 9th Feb 1995 |
| 204.238.30.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.31.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.32.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.33.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.36.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.38.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.39.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.4.0/24 | 256 | ARIN | US | 9th Feb 1995 |
| 204.238.40.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.41.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.42.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.43.0/24 | 256 | ARIN | US | 4th Mar 1995 |
| 204.238.45.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 204.238.47.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 204.238.48.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 204.238.51.0/24 | 256 | ARIN | US | 10th Mar 1995 |
| 204.238.53.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 204.238.56.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 204.238.57.0/24 | 256 | ARIN | US | 24th Apr 1995 |
| 204.238.59.0/24 | 256 | ARIN | US | 24th Apr 1995 |
| 204.238.60.0/24 | 256 | ARIN | US | 25th Apr 1995 |
| 204.238.61.0/24 | 256 | ARIN | US | 25th Apr 1995 |
| 204.238.62.0/24 | 256 | ARIN | US | 25th Apr 1995 |