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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,295 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.40.250.0/23 | 512 | ARIN |  US | 7th Oct 2014 |
| 192.40.255.0/24 | 256 | ARIN | US | 25th Sept 2025 |
| 192.40.29.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 192.40.47.0/24 | 256 | ARIN | US | 23rd May 1988 |
| 192.40.48.0/24 | 256 | ARIN | US | 23rd May 1988 |
| 192.40.50.0/24 | 256 | ARIN | US | 29th Sept 2023 |
| 192.40.53.0/24 | 256 | ARIN | US | 23rd May 1988 |
| 192.40.54.0/24 | 256 | ARIN | US | 23rd May 1988 |
| 192.40.61.0/24 | 256 | ARIN | US | 2nd Mar 2004 |
| 192.40.62.0/23 | 512 | ARIN | US | 3rd Sept 2014 |
| 192.40.64.0/24 | 256 | ARIN | US | 25th Jun 2014 |
| 192.40.65.0/24 | 256 | ARIN | US | 13th Aug 1993 |
| 192.41.137.0/24 | 256 | ARIN | US | 8th Jun 1988 |
| 192.41.138.0/23 | 512 | ARIN | US | 17th Sept 2014 |
| 192.41.161.0/24 | 256 | ARIN | US | 7th Jul 1988 |
| 192.41.163.0/24 | 256 | ARIN | US | 7th Jul 1988 |
| 192.41.173.0/24 | 256 | ARIN | US | 13th Jun 1988 |
| 192.41.174.0/24 | 256 | ARIN | US | 13th Jun 1988 |
| 192.41.175.0/24 | 256 | ARIN | US | 13th Jun 1988 |
| 192.41.176.0/24 | 256 | ARIN | US | 13th Jun 1988 |
| 192.41.198.0/24 | 256 | ARIN | US | 20th Jun 1988 |
| 192.41.199.0/24 | 256 | ARIN | US | 21st Jun 1988 |
| 192.41.205.0/24 | 256 | ARIN | US | 23rd Jun 1988 |
| 192.41.212.0/24 | 256 | ARIN | US | 13th Sept 1988 |
| 192.41.213.0/24 | 256 | ARIN | US | 4th May 1993 |
| 192.41.215.0/24 | 256 | ARIN | US | 13th Jul 1988 |
| 192.41.217.0/24 | 256 | ARIN | US | 14th Jul 1988 |
| 192.41.219.0/24 | 256 | ARIN | US | 18th Jul 1988 |
| 192.41.224.0/24 | 256 | ARIN | US | 21st Jul 1988 |
| 192.41.225.0/24 | 256 | ARIN | US | 22nd Jul 1988 |
| 192.41.238.0/24 | 256 | ARIN | US | 26th Jul 1988 |
| 192.41.239.0/24 | 256 | ARIN | US | 26th Jul 1988 |
| 192.41.240.0/22 | 1k | ARIN | US | 26th Jul 1988 |
| 192.41.244.0/24 | 256 | ARIN | US | 26th Jul 1988 |
| 192.41.247.0/24 | 256 | ARIN | US | 11th Nov 1988 |
| 192.42.10.0/23 | 512 | ARIN | US | 8th Aug 1988 |
| 192.42.108.0/24 | 256 | ARIN | US | 21st Sept 1988 |
| 192.42.109.0/24 | 256 | ARIN | US | 22nd Sept 1988 |
| 192.42.111.0/24 | 256 | ARIN | US | 29th Jun 1993 |
| 192.42.112.0/24 | 256 | ARIN | US | 18th Jul 2014 |
| 192.42.12.0/22 | 1k | ARIN | US | 8th Aug 1988 |
| 192.42.133.0/24 | 256 | ARIN | US | 27th Sept 1988 |
| 192.42.134.0/23 | 512 | ARIN | US | 27th Sept 1988 |
| 192.42.136.0/24 | 256 | ARIN | US | 27th Sept 1988 |
| 192.42.137.0/24 | 256 | ARIN | US | 4th Oct 1988 |
| 192.42.138.0/24 | 256 | ARIN | US | 4th Oct 1988 |
| 192.42.139.0/24 | 256 | ARIN | US | 4th Oct 1988 |
| 192.42.140.0/24 | 256 | ARIN | US | 4th Oct 1988 |
| 192.42.145.0/24 | 256 | ARIN | US | 7th Oct 1988 |
| 192.42.146.0/24 | 256 | ARIN | US | 10th Oct 1988 |