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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,315 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 204.126.234.0/23 | 512 | ARIN |  US | 24th Mar 1995 |
| 204.126.238.0/23 | 512 | ARIN | US | 5th Apr 1995 |
| 204.126.24.0/23 | 512 | ARIN | US | 27th Apr 2020 |
| 204.126.242.0/23 | 512 | ARIN | US | 10th Apr 1995 |
| 204.126.244.0/23 | 512 | ARIN | US | 20th Apr 1995 |
| 204.126.246.0/23 | 512 | ARIN | US | 21st Apr 1995 |
| 204.126.250.0/23 | 512 | ARIN | US | 24th Apr 1995 |
| 204.126.254.0/23 | 512 | ARIN | US | 9th Jul 2025 |
| 204.126.28.0/23 | 512 | ARIN | US | 25th Oct 1994 |
| 204.126.30.0/23 | 512 | ARIN | US | 25th Oct 1994 |
| 204.126.32.0/20 | 4.1k | ARIN | US | 19th Aug 1994 |
| 204.126.4.0/23 | 512 | ARIN | US | 27th Sept 1994 |
| 204.126.48.0/21 | 2k | ARIN | US | 19th Aug 1994 |
| 204.126.56.0/22 | 1k | ARIN | US | 19th Aug 1994 |
| 204.126.60.0/23 | 512 | ARIN | US | 19th Aug 1994 |
| 204.126.62.0/23 | 512 | ARIN | US | 25th Oct 1994 |
| 204.126.66.0/23 | 512 | ARIN | US | 26th Oct 1994 |
| 204.126.68.0/23 | 512 | ARIN | US | 26th Oct 1994 |
| 204.126.72.0/24 | 256 | ARIN | US | 26th Oct 1994 |
| 204.126.74.0/23 | 512 | ARIN | US | 2nd Nov 1994 |
| 204.126.8.0/23 | 512 | ARIN | US | 7th Oct 1994 |
| 204.126.86.0/23 | 512 | ARIN | US | 15th Nov 1994 |
| 204.126.88.0/23 | 512 | ARIN | US | 15th Nov 1994 |
| 204.126.90.0/23 | 512 | ARIN | US | 16th Nov 1994 |
| 204.126.92.0/23 | 512 | ARIN | US | 18th Nov 1994 |
| 204.126.96.0/23 | 512 | ARIN | US | 22nd Nov 1994 |
| 204.128.129.0/24 | 256 | ARIN | US | 20th Dec 1994 |
| 204.128.131.0/24 | 256 | ARIN | US | 20th Dec 1994 |
| 204.128.134.0/24 | 256 | ARIN | US | 22nd Dec 1994 |
| 204.128.135.0/24 | 256 | ARIN | US | 22nd Dec 1994 |
| 204.128.136.0/24 | 256 | ARIN | US | 22nd Dec 1994 |
| 204.128.137.0/24 | 256 | ARIN | US | 22nd Dec 1994 |
| 204.128.138.0/24 | 256 | ARIN | US | 11th Jul 1994 |
| 204.128.139.0/24 | 256 | ARIN | US | 22nd Dec 1994 |
| 204.128.140.0/24 | 256 | ARIN | US | 22nd Dec 1994 |
| 204.128.142.0/24 | 256 | ARIN | US | 22nd Dec 1994 |
| 204.128.143.0/24 | 256 | ARIN | US | 22nd Dec 1994 |
| 204.128.147.0/24 | 256 | ARIN | US | 3rd Jan 1995 |
| 204.128.148.0/24 | 256 | ARIN | US | 3rd Jan 1995 |
| 204.128.149.0/24 | 256 | ARIN | US | 3rd Jan 1995 |
| 204.128.150.0/24 | 256 | ARIN | US | 3rd Jan 1995 |
| 204.128.151.0/24 | 256 | ARIN | US | 3rd Jan 1995 |
| 204.128.152.0/24 | 256 | ARIN | US | 3rd Jan 1995 |
| 204.128.153.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 204.128.155.0/24 | 256 | ARIN | US | 7th Jan 1995 |
| 204.128.156.0/24 | 256 | ARIN | US | 7th Jan 1995 |
| 204.128.157.0/24 | 256 | ARIN | US | 7th Jan 1995 |
| 204.128.158.0/24 | 256 | ARIN | US | 7th Jan 1995 |
| 204.128.159.0/24 | 256 | ARIN | US | 7th Jan 1995 |
| 204.128.160.0/24 | 256 | ARIN | US | 7th Jan 1995 |