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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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.
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Countries with unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,300 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 205.159.212.0/24 | 256 | ARIN |  US | 14th Sept 1995 |
| 205.159.213.0/24 | 256 | ARIN | US | 14th Sept 1995 |
| 205.159.214.0/24 | 256 | ARIN | US | 14th Sept 1995 |
| 205.159.215.0/24 | 256 | ARIN | US | 20th Sept 1995 |
| 205.159.216.0/24 | 256 | ARIN | US | 20th Sept 1995 |
| 205.159.217.0/24 | 256 | ARIN | US | 20th Sept 1995 |
| 205.159.218.0/24 | 256 | ARIN | US | 20th Sept 1995 |
| 205.159.219.0/24 | 256 | ARIN | US | 20th Sept 1995 |
| 205.159.22.0/24 | 256 | ARIN | US | 10th Mar 1995 |
| 205.159.220.0/24 | 256 | ARIN | US | 20th Sept 1995 |
| 205.159.221.0/24 | 256 | ARIN | US | 20th Sept 1995 |
| 205.159.222.0/24 | 256 | ARIN | US | 20th Sept 1995 |
| 205.159.224.0/24 | 256 | ARIN | US | 20th Sept 1995 |
| 205.159.225.0/24 | 256 | ARIN | US | 21st Sept 1995 |
| 205.159.226.0/24 | 256 | ARIN | US | 21st Sept 1995 |
| 205.159.227.0/24 | 256 | ARIN | US | 21st Sept 1995 |
| 205.159.229.0/24 | 256 | ARIN | US | 25th Sept 1995 |
| 205.159.23.0/24 | 256 | ARIN | US | 6th Mar 2012 |
| 205.159.230.0/24 | 256 | ARIN | US | 25th Sept 1995 |
| 205.159.231.0/24 | 256 | ARIN | US | 25th Sept 1995 |
| 205.159.232.0/24 | 256 | ARIN | US | 25th Sept 1995 |
| 205.159.233.0/24 | 256 | ARIN | US | 25th Sept 1995 |
| 205.159.234.0/24 | 256 | ARIN | US | 25th Sept 1995 |
| 205.159.235.0/24 | 256 | ARIN | US | 25th Sept 1995 |
| 205.159.236.0/24 | 256 | ARIN | US | 25th Sept 1995 |
| 205.159.238.0/24 | 256 | ARIN | US | 28th Sept 1995 |
| 205.159.24.0/24 | 256 | ARIN | US | 14th Mar 1995 |
| 205.159.240.0/24 | 256 | ARIN | US | 28th Sept 1995 |
| 205.159.241.0/24 | 256 | ARIN | US | 29th Sept 1995 |
| 205.159.242.0/24 | 256 | ARIN | US | 29th Sept 1995 |
| 205.159.244.0/24 | 256 | ARIN | US | 8th Sept 2020 |
| 205.159.245.0/24 | 256 | ARIN | US | 4th Oct 1995 |
| 205.159.246.0/24 | 256 | ARIN | US | 4th Oct 1995 |
| 205.159.247.0/24 | 256 | ARIN | US | 5th Oct 1995 |
| 205.159.249.0/24 | 256 | ARIN | US | 5th Oct 1995 |
| 205.159.25.0/24 | 256 | ARIN | US | 14th Mar 1995 |
| 205.159.252.0/24 | 256 | ARIN | US | 5th Oct 1995 |
| 205.159.253.0/24 | 256 | ARIN | US | 5th Oct 1995 |
| 205.159.254.0/24 | 256 | ARIN | US | 6th Oct 1995 |
| 205.159.26.0/24 | 256 | ARIN | US | 14th Mar 1995 |
| 205.159.3.0/24 | 256 | ARIN | US | 9th Mar 1995 |
| 205.159.30.0/24 | 256 | ARIN | US | 14th Mar 1995 |
| 205.159.33.0/24 | 256 | ARIN | US | 14th Mar 1995 |
| 205.159.34.0/24 | 256 | ARIN | US | 7th Jan 2022 |
| 205.159.35.0/24 | 256 | ARIN | US | 15th Mar 1995 |
| 205.159.36.0/24 | 256 | ARIN | US | 15th Mar 1995 |
| 205.159.37.0/24 | 256 | ARIN | US | 15th Mar 1995 |
| 205.159.38.0/24 | 256 | ARIN | US | 15th Mar 1995 |
| 205.159.39.0/24 | 256 | ARIN | US | 15th Mar 1995 |
| 205.159.4.0/24 | 256 | ARIN | US | 9th Mar 1995 |