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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,302 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 204.69.231.0/24 | 256 | ARIN |  US | 26th Aug 1994 |
| 204.69.232.0/24 | 256 | ARIN | US | 26th Aug 1994 |
| 204.69.236.0/24 | 256 | ARIN | US | 26th Aug 1994 |
| 204.69.238.0/24 | 256 | ARIN | US | 26th Aug 1994 |
| 204.69.239.0/24 | 256 | ARIN | US | 29th Aug 1994 |
| 204.69.240.0/24 | 256 | ARIN | US | 29th Aug 1994 |
| 204.69.243.0/24 | 256 | ARIN | US | 29th Aug 1994 |
| 204.69.244.0/23 | 512 | ARIN | US | 15th Jul 2011 |
| 204.69.248.0/24 | 256 | ARIN | US | 29th Aug 1994 |
| 204.69.249.0/24 | 256 | ARIN | US | 29th Aug 1994 |
| 204.69.253.0/24 | 256 | ARIN | US | 29th Aug 1994 |
| 204.69.254.0/24 | 256 | ARIN | US | 29th Aug 1994 |
| 204.74.10.0/23 | 512 | ARIN | US | 22nd Jul 2011 |
| 204.74.123.0/24 | 256 | ARIN | US | 26th Oct 1994 |
| 204.74.124.0/23 | 512 | ARIN | US | 26th Oct 1994 |
| 204.74.127.0/24 | 256 | ARIN | US | 26th Oct 1994 |
| 204.74.207.0/24 | 256 | ARIN | US | 29th Sept 2020 |
| 204.74.32.0/19 | 8.2k | ARIN | US | 4th Aug 1994 |
| 204.74.68.0/22 | 1k | ARIN | US | 26th Oct 1994 |
| 204.74.72.0/24 | 256 | ARIN | US | 26th Oct 1994 |
| 204.74.75.0/24 | 256 | ARIN | US | 26th Oct 1994 |
| 204.74.76.0/23 | 512 | ARIN | US | 26th Oct 1994 |
| 204.74.79.0/24 | 256 | ARIN | US | 28th Jan 2022 |
| 204.74.80.0/24 | 256 | ARIN | US | 28th Jan 2022 |
| 204.74.82.0/23 | 512 | ARIN | US | 26th Oct 1994 |
| 204.74.84.0/22 | 1k | ARIN | US | 26th Oct 1994 |
| 204.74.88.0/21 | 2k | ARIN | US | 26th Oct 1994 |
| 204.74.96.0/23 | 512 | ARIN | US | 26th Oct 1994 |
| 204.75.0.0/21 | 2k | ARIN | US | 24th Jun 1994 |
| 204.75.10.0/24 | 256 | ARIN | US | 24th Jun 1994 |
| 204.75.128.0/24 | 256 | ARIN | US | 29th Aug 1994 |
| 204.75.129.0/24 | 256 | ARIN | US | 30th Aug 1994 |
| 204.75.130.0/23 | 512 | ARIN | US | 30th Aug 1994 |
| 204.75.132.0/24 | 256 | ARIN | US | 30th Aug 1994 |
| 204.75.133.0/24 | 256 | ARIN | US | 30th Aug 1994 |
| 204.75.134.0/24 | 256 | ARIN | US | 30th Aug 1994 |
| 204.75.135.0/24 | 256 | ARIN | US | 30th Aug 1994 |
| 204.75.136.0/24 | 256 | ARIN | US | 30th Aug 1994 |
| 204.75.137.0/24 | 256 | ARIN | US | 30th Aug 1994 |
| 204.75.138.0/23 | 512 | ARIN | US | 30th Aug 1994 |
| 204.75.141.0/24 | 256 | ARIN | US | 30th Aug 1994 |
| 204.75.146.0/24 | 256 | ARIN | US | 31st Aug 1994 |
| 204.75.147.0/24 | 256 | ARIN | US | 31st Aug 1994 |
| 204.75.148.0/23 | 512 | ARIN | US | 31st Aug 1994 |
| 204.75.150.0/24 | 256 | ARIN | US | 1st Sept 1994 |
| 204.75.151.0/24 | 256 | ARIN | US | 26th Aug 1994 |
| 204.75.152.0/24 | 256 | ARIN | US | 14th Jul 2026 |
| 204.75.153.0/24 | 256 | ARIN | US | 1st Sept 1994 |
| 204.75.154.0/24 | 256 | ARIN | US | 2nd Dec 1996 |
| 204.75.156.0/24 | 256 | ARIN | US | 1st Sept 1994 |