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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks registered through ARIN
30,449 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.188.141.0/24 | 256 | ARIN |  US | 10th Jul 1992 |
| 192.188.143.0/24 | 256 | ARIN | US | 13th Jul 1992 |
| 192.188.146.0/24 | 256 | ARIN | US | 12th Sept 1997 |
| 192.188.147.0/24 | 256 | ARIN | US | 14th Jul 1992 |
| 192.188.149.0/24 | 256 | ARIN | US | 14th Jul 1992 |
| 192.188.15.0/24 | 256 | ARIN | US | 17th Jun 1992 |
| 192.188.150.0/24 | 256 | ARIN | US | 14th Jul 1992 |
| 192.188.152.0/24 | 256 | ARIN | US | 15th Jul 1992 |
| 192.188.153.0/24 | 256 | ARIN | US | 15th Jul 1992 |
| 192.188.154.0/24 | 256 | ARIN | US | 15th Jul 1992 |
| 192.188.156.0/24 | 256 | ARIN | US | 16th Jul 2015 |
| 192.188.168.0/24 | 256 | ARIN |  CA | 20th Jul 1992 |
| 192.188.169.0/24 | 256 | ARIN | CA | 20th Jul 1992 |
| 192.188.17.0/24 | 256 | ARIN | US | 17th Jun 1992 |
| 192.188.173.0/24 | 256 | ARIN | US | 20th Jul 1992 |
| 192.188.18.0/24 | 256 | ARIN | US | 18th Jun 1992 |
| 192.188.181.0/24 | 256 | ARIN | US | 21st Jul 1992 |
| 192.188.184.0/24 | 256 | ARIN | US | 21st Jul 1992 |
| 192.188.188.0/24 | 256 | ARIN | US | 21st Jul 1992 |
| 192.188.19.0/24 | 256 | ARIN | US | 18th Jun 1992 |
| 192.188.190.0/24 | 256 | ARIN | US | 22nd Jul 1992 |
| 192.188.192.0/24 | 256 | ARIN | US | 23rd Jul 1992 |
| 192.188.193.0/24 | 256 | ARIN | US | 24th Jul 1992 |
| 192.188.198.0/24 | 256 | ARIN | US | 24th Jul 1992 |
| 192.188.20.0/24 | 256 | ARIN | US | 18th Jun 1992 |
| 192.188.200.0/24 | 256 | ARIN | US | 27th Jul 1992 |
| 192.188.204.0/22 | 1k | ARIN | US | 28th Jul 1992 |
| 192.188.21.0/24 | 256 | ARIN | US | 18th Jun 1992 |
| 192.188.228.0/23 | 512 | ARIN | US | 28th Jul 1992 |
| 192.188.238.0/23 | 512 | ARIN | US | 30th Jul 1992 |
| 192.188.240.0/24 | 256 | ARIN | US | 30th Jul 1992 |
| 192.188.249.0/24 | 256 | ARIN | US | 30th Jul 1992 |
| 192.188.251.0/24 | 256 | ARIN | US | 16th Jul 2015 |
| 192.188.252.0/24 | 256 | ARIN | US | 31st Jul 1992 |
| 192.188.255.0/24 | 256 | ARIN | US | 23rd Jul 2015 |
| 192.188.62.0/24 | 256 | ARIN | US | 22nd Jun 1992 |
| 192.188.66.0/24 | 256 | ARIN | US | 24th Jun 1992 |
| 192.188.67.0/24 | 256 | ARIN | US | 24th Jun 1992 |
| 192.188.68.0/24 | 256 | ARIN | US | 24th Jun 1992 |
| 192.188.70.0/24 | 256 | ARIN | US | 24th Jun 1992 |
| 192.188.93.0/24 | 256 | ARIN | US | 24th Jun 1992 |
| 192.188.97.0/24 | 256 | ARIN | US | 24th Jun 1992 |
| 192.188.98.0/24 | 256 | ARIN | US | 24th Jun 1992 |
| 192.189.0.0/24 | 256 | ARIN | CA | 3rd Oct 2025 |
| 192.189.101.0/24 | 256 | ARIN | US | 13th Jul 1992 |
| 192.189.102.0/24 | 256 | ARIN | US | 13th Jul 1992 |
| 192.189.103.0/24 | 256 | ARIN | US | 13th Jul 1992 |
| 192.189.104.0/24 | 256 | ARIN | US | 13th Jul 1992 |
| 192.189.105.0/24 | 256 | ARIN | US | 13th Jul 1992 |
| 192.189.106.0/24 | 256 | ARIN | US | 13th Jul 1992 |