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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 204.75.228.0/24 | 256 | ARIN |  US | 8th Sept 1994 |
| 204.75.230.0/24 | 256 | ARIN | US | 9th Sept 1994 |
| 204.75.231.0/24 | 256 | ARIN | US | 9th Sept 1994 |
| 204.75.232.0/22 | 1k | ARIN | US | 9th Sept 1994 |
| 204.75.236.0/23 | 512 | ARIN | US | 9th Sept 1994 |
| 204.75.238.0/24 | 256 | ARIN | US | 7th Aug 1995 |
| 204.75.239.0/24 | 256 | ARIN | US | 9th Sept 1994 |
| 204.75.24.0/21 | 2k | ARIN | US | 23rd Jun 1994 |
| 204.75.240.0/23 | 512 | ARIN | US | 9th Sept 1994 |
| 204.75.242.0/24 | 256 | ARIN | US | 9th Sept 1994 |
| 204.75.243.0/24 | 256 | ARIN | US | 9th Sept 1994 |
| 204.75.244.0/24 | 256 | ARIN | US | 9th Sept 1994 |
| 204.75.245.0/24 | 256 | ARIN | US | 9th Sept 1994 |
| 204.75.246.0/24 | 256 | ARIN | US | 9th Sept 1994 |
| 204.75.247.0/24 | 256 | ARIN | US | 9th Sept 1994 |
| 204.75.248.0/24 | 256 | ARIN | US | 12th Sept 1994 |
| 204.75.64.0/18 | 16.4k | ARIN | US | 28th Oct 1994 |
| 204.75.8.0/23 | 512 | ARIN | US | 24th Jun 1994 |
| 204.76.129.0/24 | 256 | ARIN | US | 12th Dec 1994 |
| 204.76.136.0/21 | 2k | ARIN | US | 15th Dec 1994 |
| 204.76.152.0/22 | 1k | ARIN | US | 29th Dec 1994 |
| 204.76.156.0/24 | 256 | ARIN | US | 29th Dec 1994 |
| 204.76.16.0/21 | 2k | ARIN | US | 13th Jul 1994 |
| 204.76.198.0/23 | 512 | ARIN | US | 5th Jan 1995 |
| 204.76.200.0/23 | 512 | ARIN | US | 5th Jan 1995 |
| 204.76.202.0/24 | 256 | ARIN | US | 5th Jan 1995 |
| 204.76.204.0/23 | 512 | ARIN | US | 24th Jun 2019 |
| 204.76.206.0/23 | 512 | ARIN | US | 5th Jan 1995 |
| 204.76.208.0/23 | 512 | ARIN | US | 5th Jan 1995 |
| 204.76.210.0/24 | 256 | ARIN | US | 5th Jan 1995 |
| 204.76.214.0/23 | 512 | ARIN | US | 5th Jan 1995 |
| 204.76.216.0/22 | 1k | ARIN | US | 5th Jan 1995 |
| 204.76.220.0/23 | 512 | ARIN | US | 7th Apr 2011 |
| 204.76.230.0/23 | 512 | ARIN | US | 18th Jan 1995 |
| 204.76.232.0/22 | 1k | ARIN | US | 18th Jan 1995 |
| 204.76.236.0/23 | 512 | ARIN | US | 18th Jan 1995 |
| 204.76.24.0/22 | 1k | ARIN | US | 13th Jul 1994 |
| 204.76.246.0/23 | 512 | ARIN | US | 19th Jan 1995 |
| 204.76.248.0/22 | 1k | ARIN | US | 19th Jan 1995 |
| 204.76.252.0/23 | 512 | ARIN | US | 19th Jan 1995 |
| 204.76.28.0/24 | 256 | ARIN | US | 13th Jul 1994 |
| 204.76.29.0/24 | 256 | ARIN | US | 12th Sept 2011 |
| 204.76.32.0/19 | 8.2k | ARIN | US | 24th Jun 1994 |
| 204.77.132.0/24 | 256 | ARIN | US | 22nd Aug 1995 |
| 204.77.133.0/24 | 256 | ARIN | US | 25th Jul 1996 |
| 204.77.140.0/24 | 256 | ARIN | US | 25th Apr 1996 |
| 204.77.141.0/24 | 256 | ARIN | US | 19th May 1995 |
| 204.77.142.0/24 | 256 | ARIN | US | 19th May 1995 |
| 204.77.143.0/24 | 256 | ARIN | US | 14th Feb 1995 |
| 204.77.144.0/24 | 256 | ARIN | US | 14th Feb 1995 |