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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,993 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 158.32.0.0/16 | 65.5k | ARIN |  US | 7th Feb 1992 |
| 158.33.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |
| 158.34.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |
| 158.51.138.0/23 | 512 | ARIN | US | 10th Jan 2020 |
| 158.51.160.0/24 | 256 | ARIN | US | 22nd Jan 2020 |
| 158.51.201.0/24 | 256 | ARIN | US | 13th Jan 2023 |
| 158.51.202.0/24 | 256 | ARIN | US | 17th Jan 2020 |
| 158.51.232.0/22 | 1k | ARIN | US | 3rd Feb 2020 |
| 158.51.56.0/22 | 1k | ARIN | US | 3rd Jan 2020 |
| 158.51.90.0/24 | 256 | ARIN | US | 3rd Feb 2020 |
| 158.51.91.0/24 | 256 | ARIN | US | 3rd Apr 2025 |
| 158.55.0.0/16 | 65.5k | ARIN | US | 14th Feb 1992 |
| 158.76.0.0/16 | 65.5k | ARIN | US | 16th Feb 1992 |
| 158.77.0.0/16 | 65.5k | ARIN | US | 16th Feb 1992 |
| 158.78.0.0/16 | 65.5k | ARIN | US | 16th Feb 1992 |
| 158.82.0.0/16 | 65.5k | ARIN | US | 26th Feb 1992 |
| 158.84.0.0/16 | 65.5k | ARIN | US | 19th Feb 1992 |
| 158.94.214.0/24 | 256 | RIPE NCC | US | 20th Feb 1992 |
| 158.98.0.0/16 | 65.5k | ARIN | US | 21st Feb 1992 |
| 159.102.0.0/16 | 65.5k | ARIN | US | 17th Mar 1992 |
| 159.127.44.0/22 | 1k | ARIN | US | 7th Oct 1996 |
| 159.127.48.0/20 | 4.1k | ARIN | US | 7th Oct 1996 |
| 159.129.0.0/16 | 65.5k | ARIN | US | 14th Apr 1992 |
| 159.131.0.0/16 | 65.5k | ARIN | US | 14th Apr 1992 |
| 159.132.0.0/16 | 65.5k | ARIN | US | 20th Apr 1992 |
| 159.139.0.0/16 | 65.5k | ARIN | US | 20th Apr 1992 |
| 159.161.0.0/16 | 65.5k | ARIN | US | 6th May 1992 |
| 159.163.0.0/16 | 65.5k | ARIN | US | 6th May 1992 |
| 159.164.0.0/16 | 65.5k | ARIN | US | 6th May 1992 |
| 159.165.0.0/16 | 65.5k | ARIN | US | 6th May 1992 |
| 159.17.0.0/16 | 65.5k | ARIN | US | 26th Feb 1992 |
| 159.176.0.0/16 | 65.5k | ARIN | US | 12th May 1992 |
| 159.184.0.0/14 | 262k | ARIN | US | 19th May 1992 |
| 159.188.0.0/16 | 65.5k | ARIN | US | 19th May 1992 |
| 159.198.0.0/20 | 4.1k | ARIN | US | 28th May 1992 |
| 159.198.48.0/20 | 4.1k | ARIN | US | 28th May 1992 |
| 159.198.80.0/20 | 4.1k | ARIN | US | 28th May 1992 |
| 159.198.96.0/19 | 8.2k | ARIN | US | 28th May 1992 |
| 159.199.0.0/16 | 65.5k | ARIN | US | 4th Jun 1992 |
| 159.202.0.0/16 | 65.5k | ARIN | US | 4th Jun 1992 |
| 159.214.128.0/18 | 16.4k | ARIN | US | 6th May 1992 |
| 159.222.96.0/19 | 8.2k | ARIN | US | 10th Jun 1992 |
| 159.235.0.0/16 | 65.5k | ARIN | US | 27th Jul 2018 |
| 159.236.0.0/16 | 65.5k | ARIN | US | 24th Jul 2023 |
| 159.242.192.0/22 | 1k | ARIN | US | 14th Aug 2024 |
| 159.242.196.0/22 | 1k | ARIN | US | 3rd Sept 2024 |
| 159.242.204.0/23 | 512 | ARIN | US | 14th Aug 2024 |
| 159.242.206.0/24 | 256 | ARIN | US | 3rd Sept 2024 |
| 159.249.0.0/16 | 65.5k | ARIN | US | 1st Apr 2022 |
| 159.252.0.0/16 | 65.5k | ARIN | US | 18th Jun 1992 |