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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
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Countries with unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,295 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.231.195.0/24 | 256 | ARIN |  US | 16th Oct 1992 |
| 192.231.196.0/24 | 256 | ARIN | US | 16th Oct 1992 |
| 192.231.197.0/24 | 256 | ARIN | US | 16th Oct 1992 |
| 192.231.200.0/24 | 256 | ARIN | US | 16th Oct 1992 |
| 192.231.204.0/24 | 256 | ARIN | US | 16th Oct 1992 |
| 192.231.205.0/24 | 256 | ARIN | US | 16th Oct 1992 |
| 192.231.206.0/24 | 256 | ARIN | US | 16th Oct 1992 |
| 192.231.208.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 192.231.209.0/24 | 256 | ARIN | US | 20th Oct 1992 |
| 192.231.210.0/24 | 256 | ARIN | US | 20th Oct 1992 |
| 192.231.217.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.221.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.222.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.223.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.224.0/22 | 1k | ARIN | US | 22nd Oct 1992 |
| 192.231.228.0/23 | 512 | ARIN | US | 22nd Oct 1992 |
| 192.231.232.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.235.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.236.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.239.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.240.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.241.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.242.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.245.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.250.0/23 | 512 | ARIN | US | 6th May 2015 |
| 192.231.252.0/24 | 256 | ARIN | US | 26th Oct 1992 |
| 192.231.27.0/24 | 256 | ARIN | US | 22nd Sept 1992 |
| 192.231.28.0/24 | 256 | ARIN | US | 22nd Sept 1992 |
| 192.231.3.0/24 | 256 | ARIN | US | 21st Sept 1992 |
| 192.231.31.0/24 | 256 | ARIN | US | 23rd Sept 1992 |
| 192.231.32.0/24 | 256 | ARIN | US | 23rd Sept 1992 |
| 192.231.37.0/24 | 256 | ARIN | US | 23rd Sept 1992 |
| 192.231.38.0/24 | 256 | ARIN | US | 23rd Sept 1992 |
| 192.231.4.0/24 | 256 | ARIN | US | 21st Sept 1992 |
| 192.231.42.0/24 | 256 | ARIN | US | 24th Sept 1992 |
| 192.231.44.0/24 | 256 | ARIN | US | 25th Sept 1992 |
| 192.231.45.0/24 | 256 | ARIN | US | 25th Sept 1992 |
| 192.231.46.0/24 | 256 | ARIN | US | 25th Sept 1992 |
| 192.231.47.0/24 | 256 | ARIN | US | 25th Sept 1992 |
| 192.231.48.0/24 | 256 | ARIN | US | 25th Sept 1992 |
| 192.231.49.0/24 | 256 | ARIN | US | 25th Sept 1992 |
| 192.231.50.0/23 | 512 | ARIN | US | 25th Sept 1992 |
| 192.231.52.0/24 | 256 | ARIN | US | 25th Sept 1992 |
| 192.231.53.0/24 | 256 | ARIN | US | 25th Sept 1992 |
| 192.231.54.0/24 | 256 | ARIN | US | 25th Sept 1992 |
| 192.231.55.0/24 | 256 | ARIN | US | 25th Sept 1992 |
| 192.231.57.0/24 | 256 | ARIN | US | 25th Sept 1992 |
| 192.231.58.0/24 | 256 | ARIN | US | 25th Sept 1992 |
| 192.231.6.0/24 | 256 | ARIN | US | 22nd Sept 1992 |
| 192.231.60.0/24 | 256 | ARIN | US | 25th Sept 1992 |