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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 204.138.116.0/24 | 256 | ARIN |  CA | 30th Aug 1994 |
| 204.138.138.0/23 | 512 | ARIN | CA | 30th Aug 1994 |
| 204.138.140.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.141.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.142.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.143.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.144.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.151.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.154.0/23 | 512 | ARIN | CA | 30th Aug 1994 |
| 204.138.158.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.159.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.16.0/21 | 2k | ARIN | CA | 30th Aug 1994 |
| 204.138.160.0/22 | 1k | ARIN | CA | 30th Aug 1994 |
| 204.138.164.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.166.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.170.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.171.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.172.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.173.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.174.0/23 | 512 | ARIN | CA | 30th Aug 1994 |
| 204.138.176.0/23 | 512 | ARIN | CA | 11th Oct 1994 |
| 204.138.178.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.182.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.183.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.188.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.189.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.191.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.224.0/21 | 2k | ARIN | CA | 30th Aug 1994 |
| 204.138.233.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.234.0/23 | 512 | ARIN | CA | 30th Aug 1994 |
| 204.138.236.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.237.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.238.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.239.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.24.0/23 | 512 | ARIN | CA | 30th Aug 1994 |
| 204.138.245.0/24 | 256 | ARIN | CA | 16th Sept 1994 |
| 204.138.250.0/23 | 512 | ARIN | CA | 30th Aug 1994 |
| 204.138.254.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.28.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.29.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.30.0/23 | 512 | ARIN | CA | 30th Aug 1994 |
| 204.138.32.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.34.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.35.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.36.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.37.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.38.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.39.0/24 | 256 | ARIN | CA | 12th Dec 1995 |
| 204.138.60.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.61.0/24 | 256 | ARIN | CA | 30th Aug 1994 |