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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 163.123.188.0/24 | 256 | ARIN |  US | 8th Oct 2020 |
| 163.123.190.0/24 | 256 | ARIN | US | 19th Nov 2020 |
| 163.123.196.0/24 | 256 | ARIN | US | 30th Sept 2020 |
| 163.123.224.0/24 | 256 | ARIN | US | 30th Sept 2020 |
| 163.123.225.0/24 | 256 | ARIN | US | 29th Sept 2020 |
| 163.123.248.0/22 | 1k | ARIN | US | 29th Sept 2020 |
| 163.154.0.0/16 | 65.5k | ARIN | US | 18th Jul 2018 |
| 163.165.0.0/17 | 32.8k | ARIN | US | 20th Feb 2024 |
| 163.190.0.0/16 | 65.5k | ARIN | US | 13th Aug 1992 |
| 163.231.0.0/16 | 65.5k | ARIN | US | 25th Aug 1992 |
| 163.241.0.0/16 | 65.5k | ARIN | US | 17th Sept 1992 |
| 163.243.0.0/16 | 65.5k | ARIN | US | 25th Sept 1992 |
| 163.245.32.0/19 | 8.2k | ARIN | US | 28th Sept 1992 |
| 163.245.64.0/18 | 16.4k | ARIN | US | 28th Sept 1992 |
| 163.254.0.0/16 | 65.5k | ARIN | US | 23rd Oct 1992 |
| 163.33.0.0/16 | 65.5k | ARIN | US | 6th Jul 1992 |
| 163.35.0.0/16 | 65.5k | ARIN | US | 6th Jul 1992 |
| 163.36.0.0/14 | 262k | ARIN | US | 6th Jul 1992 |
| 163.47.183.0/24 | 256 | ARIN | US | 17th Mar 2020 |
| 164.101.0.0/16 | 65.5k | ARIN | US | 4th Feb 1993 |
| 164.103.0.0/16 | 65.5k | ARIN | US | 8th Feb 1993 |
| 164.109.0.0/16 | 65.5k | ARIN | US | 18th Feb 1993 |
| 164.118.0.0/16 | 65.5k | ARIN | US | 19th Mar 1993 |
| 164.120.0.0/16 | 65.5k | ARIN | US | 8th Mar 1993 |
| 164.123.0.0/16 | 65.5k | ARIN | US | 9th Mar 1993 |
| 164.144.0.0/16 | 65.5k | ARIN | US | 9th Mar 1993 |
| 164.152.0.0/22 | 1k | ARIN | US | 12th Mar 1993 |
| 164.152.120.0/23 | 512 | ARIN | US | 12th Mar 1993 |
| 164.152.126.0/23 | 512 | ARIN | US | 12th Mar 1993 |
| 164.152.128.0/22 | 1k | ARIN | US | 12th Mar 1993 |
| 164.152.144.0/21 | 2k | ARIN | US | 12th Mar 1993 |
| 164.152.152.0/22 | 1k | ARIN | US | 12th Mar 1993 |
| 164.152.156.0/24 | 256 | ARIN | US | 12th Mar 1993 |
| 164.152.164.0/24 | 256 | ARIN | US | 12th Mar 1993 |
| 164.152.176.0/24 | 256 | ARIN | US | 12th Mar 1993 |
| 164.152.204.0/24 | 256 | ARIN | US | 12th Mar 1993 |
| 164.152.217.0/24 | 256 | ARIN | US | 12th Mar 1993 |
| 164.152.218.0/23 | 512 | ARIN | US | 12th Mar 1993 |
| 164.152.220.0/22 | 1k | ARIN | US | 12th Mar 1993 |
| 164.152.224.0/23 | 512 | ARIN | US | 12th Mar 1993 |
| 164.152.226.0/24 | 256 | ARIN | US | 12th Mar 1993 |
| 164.152.4.0/23 | 512 | ARIN | US | 12th Mar 1993 |
| 164.152.69.0/24 | 256 | ARIN | US | 12th Mar 1993 |
| 164.152.70.0/23 | 512 | ARIN | US | 12th Mar 1993 |
| 164.152.72.0/21 | 2k | ARIN | US | 12th Mar 1993 |
| 164.152.8.0/21 | 2k | ARIN | US | 17th Nov 2022 |
| 164.152.80.0/20 | 4.1k | ARIN | US | 12th Mar 1993 |
| 164.153.144.0/20 | 4.1k | ARIN | US | 14th Feb 2019 |
| 164.153.64.0/18 | 16.4k | ARIN | US | 13th Jul 2020 |
| 164.179.0.0/16 | 65.5k | ARIN | US | 16th Apr 1993 |