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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 the most unannounced blocks, largest first.
Unannounced blocks in United States
27,021 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 204.61.16.0/21 | 2k | ARIN |  US | 16th Jun 1994 |
| 204.61.160.0/19 | 8.2k | ARIN | US | 5th Jan 1995 |
| 204.61.24.0/22 | 1k | ARIN | US | 16th Jun 1994 |
| 204.61.28.0/23 | 512 | ARIN | US | 16th Jun 1994 |
| 204.61.64.0/19 | 8.2k | ARIN | US | 9th Nov 1994 |
| 204.61.96.0/19 | 8.2k | ARIN | US | 15th Dec 1994 |
| 204.62.0.0/21 | 2k | ARIN | US | 20th Jun 1994 |
| 204.62.124.0/23 | 512 | ARIN | US | 12th May 2026 |
| 204.62.126.0/24 | 256 | ARIN | US | 12th May 2026 |
| 204.62.127.0/24 | 256 | ARIN | US | 17th Jul 2015 |
| 204.62.134.0/23 | 512 | ARIN | US | 3rd Aug 1994 |
| 204.62.136.0/23 | 512 | ARIN | US | 3rd Aug 1994 |
| 204.62.138.0/24 | 256 | ARIN | US | 3rd Aug 1994 |
| 204.62.139.0/24 | 256 | ARIN | US | 3rd Aug 1994 |
| 204.62.143.0/24 | 256 | ARIN | US | 3rd Aug 1994 |
| 204.62.144.0/24 | 256 | ARIN | US | 3rd Aug 1994 |
| 204.62.146.0/24 | 256 | ARIN | US | 3rd Aug 1994 |
| 204.62.147.0/24 | 256 | ARIN | US | 3rd Aug 1994 |
| 204.62.148.0/23 | 512 | ARIN | US | 3rd Aug 1994 |
| 204.62.150.0/23 | 512 | ARIN | US | 2nd Jun 2011 |
| 204.62.152.0/24 | 256 | ARIN | US | 3rd Aug 1994 |
| 204.62.153.0/24 | 256 | ARIN | US | 3rd Aug 1994 |
| 204.62.154.0/24 | 256 | ARIN | US | 3rd Aug 1994 |
| 204.62.156.0/24 | 256 | ARIN | US | 3rd Aug 1994 |
| 204.62.158.0/24 | 256 | ARIN | US | 4th Aug 1994 |
| 204.62.161.0/24 | 256 | ARIN | US | 4th Aug 1994 |
| 204.62.162.0/23 | 512 | ARIN | US | 4th Aug 1994 |
| 204.62.164.0/22 | 1k | ARIN | US | 4th Aug 1994 |
| 204.62.168.0/23 | 512 | ARIN | US | 5th Aug 1994 |
| 204.62.170.0/24 | 256 | ARIN | US | 5th Aug 1994 |
| 204.62.171.0/24 | 256 | ARIN | US | 5th Aug 1994 |
| 204.62.172.0/22 | 1k | ARIN | US | 5th Aug 1994 |
| 204.62.176.0/24 | 256 | ARIN | US | 5th Aug 1994 |
| 204.62.177.0/24 | 256 | ARIN | US | 5th Aug 1994 |
| 204.62.178.0/24 | 256 | ARIN | US | 5th Aug 1994 |
| 204.62.179.0/24 | 256 | ARIN | US | 8th Aug 1994 |
| 204.62.180.0/24 | 256 | ARIN | US | 8th Aug 1994 |
| 204.62.181.0/24 | 256 | ARIN | US | 8th Aug 1994 |
| 204.62.182.0/24 | 256 | ARIN | US | 22nd Dec 2022 |
| 204.62.183.0/24 | 256 | ARIN | US | 8th Aug 1994 |
| 204.62.184.0/24 | 256 | ARIN | US | 8th Aug 1994 |
| 204.62.186.0/23 | 512 | ARIN | US | 8th Aug 1994 |
| 204.62.188.0/24 | 256 | ARIN | US | 8th Aug 1994 |
| 204.62.189.0/24 | 256 | ARIN | US | 8th Aug 1994 |
| 204.62.197.0/24 | 256 | ARIN | US | 10th Aug 1994 |
| 204.62.198.0/24 | 256 | ARIN | US | 10th Aug 1994 |
| 204.62.208.0/23 | 512 | ARIN | US | 10th Aug 1994 |
| 204.62.210.0/24 | 256 | ARIN | US | 10th Aug 1994 |
| 204.62.211.0/24 | 256 | ARIN | US | 10th Aug 1994 |
| 204.62.212.0/24 | 256 | ARIN | US | 10th Aug 1994 |