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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks registered through ARIN
30,431 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 148.131.0.0/16 | 65.5k | ARIN |  US | 11th Apr 1991 |
| 148.132.0.0/16 | 65.5k | ARIN | US | 11th Apr 1991 |
| 148.133.0.0/16 | 65.5k | ARIN | US | 11th Apr 1991 |
| 148.146.0.0/16 | 65.5k | ARIN | US | 18th Apr 1991 |
| 148.152.0.0/16 | 65.5k | ARIN | US | 24th Apr 1991 |
| 148.155.0.0/16 | 65.5k | ARIN | US | 30th Apr 1991 |
| 148.157.0.0/16 | 65.5k | ARIN | US | 30th Apr 1991 |
| 148.158.0.0/16 | 65.5k | ARIN | US | 30th Apr 1991 |
| 148.16.0.0/12 | 1M | ARIN | US | 13th Mar 1991 |
| 148.163.188.0/22 | 1k | ARIN | US | 5th Jun 2018 |
| 148.171.0.0/16 | 65.5k | ARIN | US | 9th May 1991 |
| 148.172.0.0/16 | 65.5k | ARIN | US | 9th May 1991 |
| 148.174.0.0/16 | 65.5k | ARIN | US | 13th May 1991 |
| 148.175.0.0/16 | 65.5k | ARIN | US | 1st Dec 1995 |
| 148.180.0.0/16 | 65.5k | ARIN | US | 15th Apr 1991 |
| 148.183.0.0/16 | 65.5k | ARIN | US | 16th May 1991 |
| 148.189.0.0/16 | 65.5k | ARIN | US | 22nd May 1991 |
| 148.190.0.0/16 | 65.5k | ARIN | US | 22nd May 1991 |
| 148.191.0.0/16 | 65.5k | ARIN | US | 22nd May 1991 |
| 148.192.0.0/16 | 65.5k | ARIN | US | 22nd May 1991 |
| 148.193.0.0/16 | 65.5k | ARIN | US | 23rd May 1991 |
| 148.194.0.0/16 | 65.5k | ARIN | US | 23rd May 1991 |
| 148.224.48.0/22 | 1k | ARIN | US | 22nd May 2025 |
| 148.50.0.0/16 | 65.5k | ARIN | US | 13th Mar 1991 |
| 148.52.160.0/19 | 8.2k | ARIN | US | 9th Sept 2025 |
| 148.59.114.0/24 | 256 | ARIN | US | 19th Apr 2018 |
| 148.59.138.0/24 | 256 | ARIN | US | 1st Jun 2026 |
| 148.59.141.0/24 | 256 | ARIN |  CA | 1st Jul 2026 |
| 148.59.144.0/24 | 256 | ARIN | US | 12th Apr 2017 |
| 148.59.155.0/24 | 256 | ARIN | US | 5th Feb 2018 |
| 148.59.166.0/23 | 512 | ARIN | US | 8th Dec 2017 |
| 148.59.206.0/23 | 512 | ARIN | US | 8th Aug 2016 |
| 148.59.216.0/23 | 512 | ARIN | CA | 29th Jun 2016 |
| 148.59.232.0/22 | 1k | ARIN | CA | 21st Nov 2025 |
| 148.59.24.0/24 | 256 | ARIN | US | 31st Aug 2020 |
| 148.59.26.0/24 | 256 | ARIN | US | 9th Oct 2020 |
| 148.59.43.0/24 | 256 | ARIN | US | 17th Aug 2018 |
| 148.59.92.0/24 | 256 | ARIN | US | 28th May 2020 |
| 148.72.129.0/24 | 256 | ARIN | US | 26th Oct 2015 |
| 148.72.146.0/23 | 512 | ARIN | US | 26th Oct 2015 |
| 148.72.148.0/24 | 256 | ARIN | US | 26th Oct 2015 |
| 148.72.150.0/23 | 512 | ARIN | US | 26th Oct 2015 |
| 148.72.156.0/23 | 512 | ARIN | US | 26th Oct 2015 |
| 148.72.180.0/22 | 1k | ARIN | US | 26th Oct 2015 |
| 148.72.184.0/21 | 2k | ARIN | US | 26th Oct 2015 |
| 148.78.67.0/24 | 256 | ARIN | US | 23rd Feb 2022 |
| 148.78.72.0/24 | 256 | ARIN | US | 23rd Feb 2022 |
| 148.78.77.0/24 | 256 | ARIN | US | 27th Dec 2017 |
| 148.78.78.0/23 | 512 | ARIN | US | 11th Apr 1991 |
| 148.78.82.0/23 | 512 | ARIN | US | 27th Dec 2017 |