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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 204.239.174.0/24 | 256 | ARIN |  CA | 1st Feb 1995 |
| 204.239.175.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.178.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.179.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.180.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.181.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.184.0/21 | 2k | ARIN | CA | 1st Feb 1995 |
| 204.239.194.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.195.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.196.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.197.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.198.0/23 | 512 | ARIN | CA | 1st Feb 1995 |
| 204.239.20.0/22 | 1k | ARIN | CA | 1st Feb 1995 |
| 204.239.200.0/23 | 512 | ARIN | CA | 1st Feb 1995 |
| 204.239.202.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.203.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.204.0/23 | 512 | ARIN |  US | 27th Oct 2025 |
| 204.239.208.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.210.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.212.0/23 | 512 | ARIN | CA | 1st Feb 1995 |
| 204.239.214.0/23 | 512 | ARIN | CA | 1st Feb 1995 |
| 204.239.217.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.218.0/23 | 512 | ARIN | CA | 1st Feb 1995 |
| 204.239.224.0/21 | 2k | ARIN | CA | 1st Feb 1995 |
| 204.239.232.0/22 | 1k | ARIN | CA | 1st Feb 1995 |
| 204.239.236.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.237.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.238.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.239.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.241.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.242.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.244.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.245.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.246.0/23 | 512 | ARIN | CA | 1st Feb 1995 |
| 204.239.25.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.254.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.31.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.32.0/21 | 2k | ARIN | CA | 1st Feb 1995 |
| 204.239.43.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.44.0/22 | 1k | ARIN | CA | 1st Feb 1995 |
| 204.239.64.0/23 | 512 | ARIN | CA | 1st Feb 1995 |
| 204.239.66.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.68.0/23 | 512 | ARIN | CA | 1st Feb 1995 |
| 204.239.72.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.73.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.74.0/23 | 512 | ARIN | CA | 1st Feb 1995 |
| 204.239.76.0/22 | 1k | ARIN | CA | 1st Feb 1995 |
| 204.239.80.0/23 | 512 | ARIN | CA | 1st Feb 1995 |
| 204.239.82.0/24 | 256 | ARIN | CA | 1st Feb 1995 |
| 204.239.86.0/24 | 256 | ARIN | CA | 1st Feb 1995 |