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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,277 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 157.146.0.0/16 | 65.5k | ARIN |  US | 10th Jan 1992 |
| 157.170.0.0/16 | 65.5k | ARIN | US | 16th Jan 1992 |
| 157.183.0.0/16 | 65.5k | ARIN | US | 22nd Jan 1992 |
| 157.184.0.0/16 | 65.5k | ARIN | US | 22nd Jan 1992 |
| 157.189.0.0/16 | 65.5k | ARIN | US | 23rd Jan 1992 |
| 157.194.0.0/16 | 65.5k | ARIN | US | 24th Jan 1992 |
| 157.195.0.0/16 | 65.5k | ARIN | US | 24th Jan 1992 |
| 157.196.0.0/16 | 65.5k | ARIN | US | 24th Jan 1992 |
| 157.198.0.0/16 | 65.5k | ARIN | US | 28th Jan 1992 |
| 157.207.128.0/17 | 32.8k | ARIN | US | 28th Jan 1992 |
| 157.207.36.0/22 | 1k | ARIN | US | 28th Jan 1992 |
| 157.207.40.0/21 | 2k | ARIN | US | 28th Jan 1992 |
| 157.207.48.0/20 | 4.1k | ARIN | US | 28th Jan 1992 |
| 157.207.68.0/22 | 1k | ARIN | US | 28th Jan 1992 |
| 157.207.72.0/21 | 2k | ARIN | US | 28th Jan 1992 |
| 157.207.80.0/20 | 4.1k | ARIN | US | 28th Jan 1992 |
| 157.207.96.0/19 | 8.2k | ARIN | US | 28th Jan 1992 |
| 157.208.128.0/17 | 32.8k | ARIN | US | 8th Jan 1992 |
| 157.208.64.0/18 | 16.4k | ARIN | US | 8th Jan 1992 |
| 157.209.0.0/16 | 65.5k | ARIN | US | 29th Jan 1992 |
| 157.212.0.0/16 | 65.5k | ARIN | US | 15th Jun 2022 |
| 157.226.0.0/16 | 65.5k | ARIN | US | 30th Jan 1992 |
| 157.239.130.0/23 | 512 | ARIN | US | 4th Feb 1992 |
| 157.239.132.0/22 | 1k | ARIN | US | 4th Feb 1992 |
| 157.239.136.0/21 | 2k | ARIN | US | 4th Feb 1992 |
| 157.239.144.0/20 | 4.1k | ARIN | US | 4th Feb 1992 |
| 157.239.160.0/19 | 8.2k | ARIN | US | 4th Feb 1992 |
| 157.251.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |
| 157.5.64.0/18 | 16.4k | ARIN | US | 12th Mar 2024 |
| 157.87.0.0/16 | 65.5k | ARIN | US | 16th Dec 1991 |
| 157.96.252.0/22 | 1k | ARIN | US | 30th Mar 2020 |
| 157.96.56.0/22 | 1k | ARIN | US | 30th Mar 2020 |
| 157.96.68.0/22 | 1k | ARIN | US | 30th Mar 2020 |
| 158.113.0.0/16 | 65.5k | ARIN | US | 26th Feb 1992 |
| 158.115.0.0/17 | 32.8k | ARIN | US | 26th Feb 1992 |
| 158.118.0.0/16 | 65.5k | ARIN | US | 27th Feb 1992 |
| 158.120.78.0/24 | 256 | ARIN | US | 14th Feb 2023 |
| 158.134.0.0/16 | 65.5k | ARIN | US | 9th Mar 1992 |
| 158.137.0.0/16 | 65.5k | ARIN | US | 6th Mar 1992 |
| 158.139.0.0/16 | 65.5k | ARIN | US | 10th Mar 1992 |
| 158.140.8.0/21 | 2k | ARIN | US | 1st Jun 2016 |
| 158.146.160.0/19 | 8.2k | ARIN | US | 12th Mar 1992 |
| 158.146.192.0/18 | 16.4k | ARIN | US | 12th Mar 1992 |
| 158.159.0.0/16 | 65.5k | ARIN | US | 17th Mar 1992 |
| 158.164.0.0/16 | 65.5k | ARIN | US | 18th Mar 1992 |
| 158.171.0.0/16 | 65.5k | ARIN | US | 23rd Mar 1992 |
| 158.183.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 158.184.0.0/23 | 512 | ARIN | US | 25th Mar 1992 |
| 158.184.104.0/22 | 1k | ARIN | US | 25th Mar 1992 |
| 158.184.108.0/23 | 512 | ARIN | US | 25th Mar 1992 |