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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 204.29.207.0/24 | 256 | ARIN |  US | 16th Sept 2019 |
| 204.29.208.0/24 | 256 | ARIN | US | 28th Jun 1994 |
| 204.29.210.0/24 | 256 | ARIN | US | 29th Jun 1994 |
| 204.29.211.0/24 | 256 | ARIN | US | 29th Jun 1994 |
| 204.29.212.0/24 | 256 | ARIN | US | 29th Jun 1994 |
| 204.29.216.0/24 | 256 | ARIN | US | 30th Jun 1994 |
| 204.29.217.0/24 | 256 | ARIN | US | 30th Jun 1994 |
| 204.29.218.0/24 | 256 | ARIN | US | 30th Jun 1994 |
| 204.29.219.0/24 | 256 | ARIN | US | 30th Jun 1994 |
| 204.29.224.0/24 | 256 | ARIN | US | 30th Jun 1994 |
| 204.29.225.0/24 | 256 | ARIN | US | 30th Jun 1994 |
| 204.29.234.0/24 | 256 | ARIN | US | 30th Jun 1994 |
| 204.29.235.0/24 | 256 | ARIN | US | 30th Jun 1994 |
| 204.29.237.0/24 | 256 | ARIN | US | 30th Jun 1994 |
| 204.29.238.0/24 | 256 | ARIN | US | 1st Jul 1994 |
| 204.29.239.0/24 | 256 | ARIN | US | 1st Jul 1994 |
| 204.29.240.0/23 | 512 | ARIN | US | 1st Jul 1994 |
| 204.29.242.0/24 | 256 | ARIN | US | 1st Jul 1994 |
| 204.29.248.0/24 | 256 | ARIN | US | 1st Jul 1994 |
| 204.29.249.0/24 | 256 | ARIN | US | 1st Jul 1994 |
| 204.29.250.0/24 | 256 | ARIN | US | 1st Jul 1994 |
| 204.29.251.0/24 | 256 | ARIN | US | 1st Jul 2026 |
| 204.29.252.0/24 | 256 | ARIN | US | 5th Jul 1994 |
| 204.29.253.0/24 | 256 | ARIN | US | 5th Jul 1994 |
| 204.29.254.0/24 | 256 | ARIN | US | 5th Jul 1994 |
| 204.29.255.0/24 | 256 | ARIN | US | 5th Jul 1994 |
| 204.29.32.0/20 | 4.1k | ARIN | US | 22nd Jun 1994 |
| 204.29.48.0/21 | 2k | ARIN | US | 22nd Jun 1994 |
| 204.29.56.0/22 | 1k | ARIN | US | 22nd Jun 1994 |
| 204.29.62.0/23 | 512 | ARIN | US | 22nd Jun 1994 |
| 204.29.8.0/23 | 512 | ARIN | US | 29th Jun 1994 |
| 204.31.0.0/17 | 32.8k | ARIN | US | 2nd Aug 2000 |
| 204.31.128.0/18 | 16.4k | ARIN | US | 2nd Aug 2000 |
| 204.31.224.0/19 | 8.2k | ARIN | US | 12th May 1994 |
| 204.32.0.0/17 | 32.8k | ARIN | US | 12th May 1994 |
| 204.32.144.0/20 | 4.1k | ARIN | US | 12th May 1994 |
| 204.32.160.0/19 | 8.2k | ARIN | US | 12th May 1994 |
| 204.32.192.0/19 | 8.2k | ARIN | US | 12th May 1994 |
| 204.33.144.0/20 | 4.1k | ARIN | US | 12th May 1994 |
| 204.44.0.0/20 | 4.1k | ARIN | US | 24th May 1994 |
| 204.44.144.0/21 | 2k | ARIN | US | 27th Dec 1994 |
| 204.44.152.0/22 | 1k | ARIN | US | 27th Dec 1994 |
| 204.44.156.0/24 | 256 | ARIN | US | 27th Dec 1994 |
| 204.44.157.0/24 | 256 | ARIN | US | 25th Jul 2011 |
| 204.44.208.0/20 | 4.1k | ARIN | US | 7th Feb 1995 |
| 204.44.224.0/20 | 4.1k | ARIN | US | 16th Feb 1995 |
| 204.44.32.0/20 | 4.1k | ARIN | US | 18th May 1994 |
| 204.44.48.0/21 | 2k | ARIN | US | 18th May 1994 |
| 204.44.56.0/24 | 256 | ARIN | US | 18th May 1994 |
| 204.44.58.0/23 | 512 | ARIN | US | 2nd Sept 2011 |