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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks in Canada
3,775 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 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 |
| 204.138.62.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.63.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.64.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.65.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.66.0/24 | 256 | ARIN | CA | 1st Jan 1995 |
| 204.138.67.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.69.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.70.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.73.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.8.0/21 | 2k | ARIN | CA | 30th Aug 1994 |
| 204.138.88.0/23 | 512 | ARIN | CA | 30th Aug 1994 |
| 204.138.90.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.91.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.92.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.93.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.96.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.145.226.0/24 | 256 | ARIN | CA | 3rd Oct 2025 |
| 204.145.229.0/24 | 256 | ARIN | CA | 23rd Jan 1995 |
| 204.15.184.0/21 | 2k | ARIN | CA | 19th Sept 2005 |
| 204.153.123.0/24 | 256 | ARIN | CA | 2nd Apr 2026 |
| 204.153.206.0/23 | 512 | ARIN | CA | 5th Feb 2020 |
| 204.156.124.0/22 | 1k | ARIN | CA | 12th Feb 2009 |
| 204.17.154.0/24 | 256 | ARIN | CA | 7th Jan 2011 |