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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
Browse by country
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 |
|---|---|---|---|---|
| 164.12.0.0/16 | 65.5k | RIPE NCC |  US | 2nd Nov 1992 |
| 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 |
| 164.177.184.0/21 | 2k | RIPE NCC | US | 21st Nov 2011 |
| 164.179.0.0/16 | 65.5k | ARIN | US | 16th Apr 1993 |
| 164.55.0.0/17 | 32.8k | ARIN | US | 9th Dec 1992 |
| 164.55.128.0/18 | 16.4k | ARIN | US | 9th Dec 1992 |
| 164.55.192.0/19 | 8.2k | ARIN | US | 9th Dec 1992 |
| 164.56.0.0/16 | 65.5k | ARIN | US | 5th Dec 1992 |
| 164.57.0.0/17 | 32.8k | ARIN | US | 5th Dec 1992 |
| 164.57.128.0/18 | 16.4k | ARIN | US | 5th Dec 1992 |
| 164.57.224.0/19 | 8.2k | ARIN | US | 5th Dec 1992 |
| 164.68.0.0/18 | 16.4k | ARIN | US | 17th Dec 1992 |
| 164.72.0.0/16 | 65.5k | ARIN | US | 16th Nov 1992 |
| 164.79.0.0/16 | 65.5k | ARIN | US | 29th Dec 1992 |
| 164.84.0.0/16 | 65.5k | ARIN | US | 11th Jan 1993 |
| 164.89.0.0/16 | 65.5k | ARIN | US | 21st Jan 1993 |
| 164.91.0.0/16 | 65.5k | ARIN | US | 25th Jan 1993 |
| 164.93.0.0/17 | 32.8k | ARIN | US | 11th Jul 2023 |
| 165.100.160.0/20 | 4.1k | ARIN | US | 26th Jun 2024 |
| 165.105.0.0/16 | 65.5k | ARIN | US | 12th May 1993 |
| 165.116.0.0/16 | 65.5k | ARIN | US | 20th May 1993 |
| 165.126.0.0/16 | 65.5k | ARIN | US | 1st Jun 1993 |
| 165.135.0.0/16 | 65.5k | ARIN | US | 9th Jun 1993 |
| 165.136.0.0/16 | 65.5k | ARIN | US | 9th Jun 1993 |
| 165.140.0.0/22 | 1k | ARIN | US | 7th Jan 2022 |