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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,249 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 170.176.0.0/17 | 32.8k | ARIN |  US | 18th Aug 1994 |
| 170.178.0.0/17 | 32.8k | ARIN | US | 7th Mar 1994 |
| 170.178.148.0/22 | 1k | ARIN | US | 18th May 2026 |
| 170.178.152.0/22 | 1k | ARIN | US | 18th Mar 2026 |
| 170.187.64.0/18 | 16.4k | ARIN | US | 12th Sept 1994 |
| 170.192.0.0/16 | 65.5k | ARIN | US | 23rd Sept 1994 |
| 170.196.0.0/16 | 65.5k | ARIN | US | 7th Oct 1994 |
| 170.197.0.0/16 | 65.5k | ARIN | US | 11th Oct 1994 |
| 170.198.0.0/16 | 65.5k | ARIN | US | 14th Oct 2026 |
| 170.199.210.0/23 | 512 | ARIN | US | 11th May 2018 |
| 170.199.212.0/22 | 1k | ARIN | US | 11th May 2018 |
| 170.199.216.0/23 | 512 | ARIN | US | 11th May 2018 |
| 170.199.238.0/23 | 512 | ARIN | US | 23rd Nov 2020 |
| 170.199.247.0/24 | 256 | ARIN | US | 10th Nov 1994 |
| 170.205.20.0/22 | 1k | ARIN | US | 5th Jul 2023 |
| 170.214.0.0/16 | 65.5k | ARIN | US | 9th Feb 1995 |
| 170.224.192.0/18 | 16.4k | ARIN | US | 21st Apr 1995 |
| 170.225.144.0/20 | 4.1k | ARIN | US | 21st Apr 1995 |
| 170.225.224.0/23 | 512 | ARIN | US | 21st Apr 1995 |
| 170.225.227.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 170.225.228.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 170.225.229.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 170.225.230.0/23 | 512 | ARIN | US | 21st Apr 1995 |
| 170.225.232.0/23 | 512 | ARIN | US | 21st Apr 1995 |
| 170.225.234.0/23 | 512 | ARIN | US | 21st Apr 1995 |
| 170.225.236.0/22 | 1k | ARIN | US | 21st Apr 1995 |
| 170.225.240.0/23 | 512 | ARIN | US | 21st Apr 1995 |
| 170.225.242.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 170.225.243.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 170.225.244.0/22 | 1k | ARIN | US | 21st Apr 1995 |
| 170.225.248.0/22 | 1k | ARIN | US | 21st Apr 1995 |
| 170.225.252.0/22 | 1k | ARIN | US | 21st Apr 1995 |
| 170.225.32.0/19 | 8.2k | ARIN | US | 21st Apr 1995 |
| 170.225.64.0/19 | 8.2k | ARIN | US | 21st Apr 1995 |
| 170.225.96.0/20 | 4.1k | ARIN | US | 21st Apr 1995 |
| 170.226.0.0/19 | 8.2k | ARIN | US | 21st Apr 1995 |
| 170.226.128.0/17 | 32.8k | ARIN | US | 21st Apr 1995 |
| 170.226.32.0/20 | 4.1k | ARIN | US | 21st Apr 1995 |
| 170.226.48.0/21 | 2k | ARIN | US | 21st Apr 1995 |
| 170.226.56.0/23 | 512 | ARIN | US | 21st Apr 1995 |
| 170.226.58.0/23 | 512 | ARIN | US | 21st Apr 1995 |
| 170.226.60.0/22 | 1k | ARIN | US | 21st Apr 1995 |
| 170.226.64.0/18 | 16.4k | ARIN | US | 21st Apr 1995 |
| 170.227.0.0/16 | 65.5k | ARIN | US | 21st Apr 1995 |
| 170.234.0.0/16 | 65.5k | ARIN | US | 13th May 1994 |
| 170.240.0.0/14 | 262k | ARIN | US | 3rd Mar 1998 |
| 170.248.14.0/23 | 512 | ARIN | US | 24th Jan 1994 |
| 170.248.184.0/22 | 1k | ARIN | US | 24th Jan 1994 |
| 170.248.2.0/23 | 512 | ARIN | US | 24th Jan 1994 |
| 170.249.92.0/22 | 1k | ARIN | US | 6th Mar 2019 |