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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,124 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.137.99.0/24 | 256 | ARIN |  US | 20th May 1992 |
| 192.138.1.0/24 | 256 | RIPE NCC |  GB | 2nd Jan 1992 |
| 192.138.10.0/23 | 512 | ARIN | US | 4th Feb 2015 |
| 192.138.102.0/24 | 256 | ARIN | US | 7th Jan 1992 |
| 192.138.103.0/24 | 256 | ARIN | US | 7th Jan 1992 |
| 192.138.104.0/24 | 256 | ARIN | US | 7th Jan 1992 |
| 192.138.105.0/24 | 256 | RIPE NCC |  NO | 7th Jan 1992 |
| 192.138.106.0/23 | 512 | RIPE NCC | NO | 7th Jan 1992 |
| 192.138.108.0/24 | 256 | RIPE NCC | NO | 7th Jan 1992 |
| 192.138.112.0/22 | 1k | RIPE NCC |  SE | 7th Jan 1992 |
| 192.138.118.0/23 | 512 | APNIC | US | 21st Jan 2011 |
| 192.138.120.0/22 | 1k | APNIC | US | 11th Feb 2011 |
| 192.138.124.0/23 | 512 | APNIC | US | 11th Feb 2011 |
| 192.138.126.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.127.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.131.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.132.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.134.0/24 | 256 | ARIN | US | 7th Jan 1992 |
| 192.138.135.0/24 | 256 | ARIN | US | 7th Jan 1992 |
| 192.138.136.0/24 | 256 | ARIN | US | 7th Jan 1992 |
| 192.138.138.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.139.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.140.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.141.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.142.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.143.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.144.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.145.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.146.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.147.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.149.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.150.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.151.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.152.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.154.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.155.0/24 | 256 | RIPE NCC | NO | 8th Jan 1992 |
| 192.138.156.0/23 | 512 | RIPE NCC | GB | 8th Jan 1992 |
| 192.138.158.0/24 | 256 | RIPE NCC | GB | 8th Jan 1992 |
| 192.138.159.0/24 | 256 | ARIN | US | 8th Jan 1992 |
| 192.138.163.0/24 | 256 | ARIN | US | 12th Jul 2019 |
| 192.138.164.0/24 | 256 | ARIN | US | 8th Oct 2021 |
| 192.138.166.0/24 | 256 | ARIN | US | 10th Jan 1992 |
| 192.138.167.0/24 | 256 | ARIN | US | 10th Jan 1992 |
| 192.138.169.0/24 | 256 | ARIN | US | 10th Jan 1992 |
| 192.138.170.0/24 | 256 | ARIN | US | 10th Jan 1992 |
| 192.138.171.0/24 | 256 | ARIN | US | 10th Jan 1992 |
| 192.138.173.0/24 | 256 | ARIN | US | 13th Jan 1992 |
| 192.138.175.0/24 | 256 | ARIN | US | 13th Jan 1992 |
| 192.138.179.0/24 | 256 | ARIN | US | 13th Jan 1992 |
| 192.138.180.0/24 | 256 | ARIN | US | 13th Jan 1992 |