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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
30,449 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.175.9.0/24 | 256 | ARIN |  US | 28th May 1992 |
| 192.18.0.0/17 | 32.8k | ARIN | US | 9th Sept 1985 |
| 192.18.192.0/23 | 512 | ARIN | US | 9th Sept 1985 |
| 192.18.194.0/24 | 256 | ARIN | US | 9th Sept 1985 |
| 192.18.208.0/20 | 4.1k | ARIN | US | 9th Sept 1985 |
| 192.18.224.0/19 | 8.2k | ARIN | US | 9th Sept 1985 |
| 192.180.0.0/15 | 131k | ARIN | US | 26th Sept 2012 |
| 192.184.4.0/24 | 256 | ARIN | US | 8th Oct 1990 |
| 192.184.8.0/21 | 2k | ARIN | US | 7th Mar 2013 |
| 192.187.10.0/24 | 256 | ARIN | US | 19th Jun 1992 |
| 192.187.11.0/24 | 256 | ARIN | US | 19th Jun 1992 |
| 192.187.12.0/24 | 256 | ARIN | US | 19th Jun 1992 |
| 192.187.128.0/24 | 256 | ARIN | US | 30th Dec 1992 |
| 192.187.129.0/24 | 256 | ARIN | US | 8th Jan 1993 |
| 192.187.13.0/24 | 256 | ARIN | US | 19th Jun 1992 |
| 192.187.130.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.132.0/24 | 256 | ARIN | US | 8th Jan 1993 |
| 192.187.133.0/24 | 256 | ARIN | US | 8th Jan 1993 |
| 192.187.134.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.135.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.136.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.14.0/24 | 256 | ARIN | US | 19th Jun 1992 |
| 192.187.140.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.141.0/24 | 256 | ARIN | US | 28th Jan 1993 |
| 192.187.142.0/24 | 256 | ARIN | US | 7th Jan 1993 |
| 192.187.143.0/24 | 256 | ARIN | US | 28th Jan 1993 |
| 192.187.148.0/24 | 256 | ARIN | US | 7th Jan 1993 |
| 192.187.149.0/24 | 256 | ARIN | US | 3rd Feb 1993 |
| 192.187.150.0/24 | 256 | ARIN | US | 21st Dec 1992 |
| 192.187.151.0/24 | 256 | ARIN | US | 9th Feb 1993 |
| 192.187.152.0/24 | 256 | ARIN | US | 9th Feb 1993 |
| 192.187.153.0/24 | 256 | ARIN | US | 3rd Feb 1993 |
| 192.187.154.0/24 | 256 | ARIN | US | 9th Feb 1993 |
| 192.187.155.0/24 | 256 | ARIN | US | 3rd Feb 1993 |
| 192.187.156.0/24 | 256 | ARIN | US | 3rd Feb 1993 |
| 192.187.157.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.158.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.159.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.160.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.161.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.162.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.163.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.164.0/24 | 256 | ARIN | US | 3rd Feb 1993 |
| 192.187.165.0/24 | 256 | ARIN | US | 30th Jan 1993 |
| 192.187.166.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.167.0/24 | 256 | ARIN | US | 17th Jul 1992 |
| 192.187.168.0/21 | 2k | ARIN | US | 20th Jan 1993 |
| 192.187.176.0/20 | 4.1k | ARIN | US | 20th Jan 1993 |
| 192.187.32.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.33.0/24 | 256 | ARIN | US | 29th Jun 1992 |