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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 in United States
26,289 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.187.53.0/24 | 256 | ARIN |  US | 29th Jun 1992 |
| 192.187.54.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.55.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.56.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.57.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.58.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.59.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.60.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.61.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.64.0/19 | 8.2k | ARIN | US | 29th Jun 1992 |
| 192.187.9.0/24 | 256 | ARIN | US | 19th Jun 1992 |
| 192.188.1.0/24 | 256 | ARIN | US | 11th Jun 1992 |
| 192.188.102.0/24 | 256 | ARIN | US | 25th Jun 1992 |
| 192.188.103.0/24 | 256 | ARIN | US | 26th Jun 1992 |
| 192.188.104.0/24 | 256 | ARIN | US | 26th Jun 1992 |
| 192.188.109.0/24 | 256 | ARIN | US | 26th Jun 1992 |
| 192.188.110.0/24 | 256 | ARIN | US | 26th Jun 1992 |
| 192.188.111.0/24 | 256 | ARIN | US | 26th Jun 1992 |
| 192.188.112.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.188.113.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.188.114.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.188.118.0/24 | 256 | ARIN | US | 1st Jul 1992 |
| 192.188.12.0/24 | 256 | ARIN | US | 16th Jun 1992 |
| 192.188.120.0/24 | 256 | ARIN | US | 7th Dec 2024 |
| 192.188.13.0/24 | 256 | ARIN | US | 17th Jun 1992 |
| 192.188.133.0/24 | 256 | ARIN | US | 8th Jul 1992 |
| 192.188.134.0/24 | 256 | ARIN | US | 8th Jul 1992 |
| 192.188.138.0/24 | 256 | ARIN | US | 10th Jul 1992 |
| 192.188.139.0/24 | 256 | ARIN | US | 10th Jul 1992 |
| 192.188.14.0/24 | 256 | ARIN | US | 17th Jun 1992 |
| 192.188.140.0/24 | 256 | ARIN | US | 10th Jul 1992 |
| 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 |
| 192.188.17.0/24 | 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 |