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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,315 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 199.245.186.0/24 | 256 | ARIN |  US | 19th May 1994 |
| 199.245.187.0/24 | 256 | ARIN | US | 19th May 1994 |
| 199.245.190.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.191.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.192.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.193.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.194.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.195.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.196.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.198.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.199.0/24 | 256 | ARIN | US | 2nd Dec 2025 |
| 199.245.201.0/24 | 256 | ARIN | US | 23rd May 1994 |
| 199.245.202.0/24 | 256 | ARIN | US | 23rd May 1994 |
| 199.245.203.0/24 | 256 | ARIN | US | 16th Aug 1994 |
| 199.245.207.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.210.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.211.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.212.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.213.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.215.0/24 | 256 | ARIN | US | 20th May 1994 |
| 199.245.224.0/24 | 256 | ARIN | US | 23rd May 1994 |
| 199.245.226.0/24 | 256 | ARIN | US | 23rd May 1994 |
| 199.245.231.0/24 | 256 | ARIN | US | 24th May 1994 |
| 199.245.232.0/24 | 256 | ARIN | US | 24th May 1994 |
| 199.245.239.0/24 | 256 | ARIN | US | 24th May 1994 |
| 199.245.240.0/24 | 256 | ARIN | US | 24th May 1994 |
| 199.245.243.0/24 | 256 | ARIN | US | 25th May 1994 |
| 199.245.246.0/24 | 256 | ARIN | US | 25th May 1994 |
| 199.245.247.0/24 | 256 | ARIN | US | 25th May 1994 |
| 199.245.248.0/24 | 256 | ARIN | US | 25th May 1994 |
| 199.245.249.0/24 | 256 | ARIN | US | 25th May 1994 |
| 199.245.250.0/24 | 256 | ARIN | US | 25th May 1994 |
| 199.245.251.0/24 | 256 | ARIN | US | 25th May 1994 |
| 199.245.252.0/24 | 256 | ARIN | US | 25th May 1994 |
| 199.245.254.0/24 | 256 | ARIN | US | 25th May 1994 |
| 199.245.32.0/20 | 4.1k | ARIN | US | 2nd Jun 1994 |
| 199.245.48.0/22 | 1k | ARIN | US | 2nd Jun 1994 |
| 199.245.64.0/24 | 256 | ARIN | US | 15th Jul 1994 |
| 199.245.65.0/24 | 256 | ARIN | US | 15th Jul 1994 |
| 199.245.66.0/23 | 512 | ARIN | US | 15th Jul 1994 |
| 199.245.68.0/24 | 256 | ARIN | US | 15th Jul 1994 |
| 199.245.69.0/24 | 256 | ARIN | US | 15th Jul 1994 |
| 199.245.70.0/24 | 256 | ARIN | US | 18th Jul 1994 |
| 199.245.71.0/24 | 256 | ARIN | US | 6th Jul 2026 |
| 199.245.72.0/24 | 256 | ARIN | US | 18th Jul 1994 |
| 199.245.73.0/24 | 256 | ARIN | US | 26th Dec 2024 |
| 199.245.74.0/23 | 512 | ARIN | US | 18th Jul 1994 |
| 199.245.76.0/22 | 1k | ARIN | US | 18th Jul 1994 |
| 199.245.80.0/24 | 256 | ARIN | US | 18th Jul 1994 |
| 199.245.81.0/24 | 256 | ARIN | US | 18th Jul 1994 |