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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,273 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 129.41.184.0/22 | 1k | ARIN |  US | 29th Jul 1987 |
| 129.41.188.0/23 | 512 | ARIN | US | 29th Jul 1987 |
| 129.41.190.0/23 | 512 | ARIN | US | 29th Jul 1987 |
| 129.41.208.0/23 | 512 | ARIN | US | 29th Jul 1987 |
| 129.41.210.0/23 | 512 | ARIN | US | 29th Jul 1987 |
| 129.41.212.0/22 | 1k | ARIN | US | 29th Jul 1987 |
| 129.41.217.0/24 | 256 | ARIN | US | 29th Jul 1987 |
| 129.41.218.0/23 | 512 | ARIN | US | 29th Jul 1987 |
| 129.41.223.0/24 | 256 | ARIN | US | 29th Jul 1987 |
| 129.41.36.0/22 | 1k | ARIN | US | 29th Jul 1987 |
| 129.41.42.0/24 | 256 | ARIN | US | 29th Jul 1987 |
| 129.41.43.0/24 | 256 | ARIN | US | 29th Jul 1987 |
| 129.41.44.0/24 | 256 | ARIN | US | 29th Jul 1987 |
| 129.41.48.0/22 | 1k | ARIN | US | 29th Jul 1987 |
| 129.41.54.0/23 | 512 | ARIN | US | 29th Jul 1987 |
| 129.41.60.0/23 | 512 | ARIN | US | 29th Jul 1987 |
| 129.41.64.0/21 | 2k | ARIN | US | 29th Jul 1987 |
| 129.41.80.0/22 | 1k | ARIN | US | 29th Jul 1987 |
| 129.41.92.0/23 | 512 | ARIN | US | 29th Jul 1987 |
| 129.41.94.0/24 | 256 | ARIN | US | 29th Jul 1987 |
| 129.41.96.0/20 | 4.1k | ARIN | US | 29th Jul 1987 |
| 129.50.0.0/16 | 65.5k | ARIN | US | 5th Aug 1987 |
| 129.58.0.0/16 | 65.5k | ARIN | US | 7th Aug 1987 |
| 129.75.0.0/16 | 65.5k | ARIN | US | 19th Nov 2014 |
| 129.76.0.0/16 | 65.5k | ARIN | US | 25th Sept 1987 |
| 129.86.0.0/16 | 65.5k | ARIN | US | 15th Oct 1987 |
| 13.129.0.0/16 | 65.5k | ARIN | US | 25th Apr 1986 |
| 13.131.0.0/16 | 65.5k | ARIN | US | 25th Apr 1986 |
| 13.132.0.0/15 | 131k | ARIN | US | 25th Apr 1986 |
| 13.136.0.0/14 | 262k | ARIN | US | 25th Apr 1986 |
| 13.145.0.0/16 | 65.5k | ARIN | US | 25th Apr 1986 |
| 13.147.0.0/16 | 65.5k | ARIN | US | 25th Apr 1986 |
| 13.148.0.0/15 | 131k | ARIN | US | 25th Apr 1986 |
| 13.150.0.0/15 | 131k | ARIN | US | 19th Dec 2022 |
| 13.153.0.0/16 | 65.5k | ARIN | US | 25th Apr 1986 |
| 13.155.0.0/16 | 65.5k | ARIN | US | 25th Apr 1986 |
| 13.156.0.0/15 | 131k | ARIN | US | 25th Apr 1986 |
| 13.161.0.0/16 | 65.5k | ARIN | US | 25th Apr 1986 |
| 13.163.0.0/16 | 65.5k | ARIN | US | 25th Apr 1986 |
| 13.164.0.0/15 | 131k | ARIN | US | 25th Apr 1986 |
| 13.184.0.0/13 | 524k | ARIN | US | 28th Sept 2021 |
| 13.96.0.0/13 | 524k | ARIN | US | 26th Mar 2015 |
| 130.1.0.0/16 | 65.5k | ARIN | US | 25th Sept 1992 |
| 130.10.0.0/16 | 65.5k | ARIN | US | 25th Sept 1992 |
| 130.103.0.0/16 | 65.5k | ARIN | US | 18th Jul 1988 |
| 130.106.0.0/16 | 65.5k | ARIN | US | 20th Jul 1988 |
| 130.12.105.0/24 | 256 | ARIN | US | 8th Oct 2025 |
| 130.12.107.0/24 | 256 | ARIN | US | 17th Oct 2025 |
| 130.12.108.0/24 | 256 | ARIN | US | 13th Oct 2025 |
| 130.12.109.0/24 | 256 | ARIN | US | 8th Oct 2025 |