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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,149 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 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 |
| 192.187.34.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.35.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.36.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.37.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.38.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.39.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.40.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.41.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.42.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.43.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.44.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.45.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.46.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.47.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.48.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.49.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.50.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.51.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 192.187.52.0/24 | 256 | ARIN | US | 29th Jun 1992 |
| 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 |