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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 192.138.181.0/24 | 256 | ARIN |  US | 14th Jan 1992 |
| 192.138.183.0/24 | 256 | RIPE NCC |  TR | 29th Apr 2024 |
| 192.138.184.0/24 | 256 | ARIN | US | 14th Jan 1992 |
| 192.138.188.0/24 | 256 | APNIC |  SG | 7th Jan 2011 |
| 192.138.190.0/24 | 256 | ARIN | US | 14th Jan 1992 |
| 192.138.192.0/24 | 256 | RIPE NCC |  GB | 15th Jan 1992 |
| 192.138.195.0/24 | 256 | ARIN | US | 15th Jan 1992 |
| 192.138.196.0/24 | 256 | ARIN | US | 15th Jan 1992 |
| 192.138.197.0/24 | 256 | ARIN | US | 15th Jan 1992 |
| 192.138.198.0/24 | 256 | ARIN | US | 16th Jan 1992 |
| 192.138.199.0/24 | 256 | ARIN | US | 16th Jan 1992 |
| 192.138.2.0/23 | 512 | RIPE NCC | GB | 2nd Jan 1992 |
| 192.138.200.0/24 | 256 | ARIN | US | 16th Jan 1992 |
| 192.138.202.0/24 | 256 | ARIN | US | 16th Jan 1992 |
| 192.138.206.0/24 | 256 | ARIN | US | 29th Jun 2023 |
| 192.138.207.0/24 | 256 | ARIN | US | 3rd Feb 1992 |
| 192.138.208.0/24 | 256 | ARIN | US | 26th Feb 1992 |
| 192.138.212.0/24 | 256 | ARIN | US | 3rd Jun 2015 |
| 192.138.215.0/24 | 256 | ARIN | US | 3rd Mar 1996 |
| 192.138.216.0/24 | 256 | ARIN | US | 3rd Apr 1992 |
| 192.138.217.0/24 | 256 | ARIN | US | 4th May 1992 |
| 192.138.218.0/23 | 512 | ARIN | US | 18th Feb 2015 |
| 192.138.221.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.138.222.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.138.223.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.138.224.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.138.227.0/24 | 256 | ARIN | US | 2nd Jul 2015 |
| 192.138.229.0/24 | 256 | RIPE NCC | GB | 17th Jan 1992 |
| 192.138.230.0/24 | 256 | RIPE NCC |  CH | 17th Jan 1992 |
| 192.138.231.0/24 | 256 | RIPE NCC | CH | 17th Jan 1992 |
| 192.138.232.0/24 | 256 | RIPE NCC | CH | 17th Jan 1992 |
| 192.138.233.0/24 | 256 | ARIN | US | 17th Jan 1992 |
| 192.138.234.0/24 | 256 | ARIN | US | 17th Jan 1992 |
| 192.138.235.0/24 | 256 | ARIN | US | 17th Jan 1992 |
| 192.138.236.0/24 | 256 | ARIN | US | 17th Jan 1992 |
| 192.138.237.0/24 | 256 | ARIN | US | 12th May 1992 |
| 192.138.238.0/24 | 256 | ARIN | US | 21st Jan 1992 |
| 192.138.239.0/24 | 256 | ARIN | US | 21st Jan 1992 |
| 192.138.240.0/21 | 2k | ARIN | US | 21st Jan 1992 |
| 192.138.248.0/24 | 256 | RIPE NCC | GB | 22nd Jan 1992 |
| 192.138.250.0/24 | 256 | ARIN | US | 22nd Jan 1992 |
| 192.138.252.0/24 | 256 | ARIN | US | 22nd Jan 1992 |
| 192.138.253.0/24 | 256 | ARIN | US | 22nd Jan 1992 |
| 192.138.254.0/24 | 256 | ARIN | US | 22nd Jan 1992 |
| 192.138.255.0/24 | 256 | ARIN | US | 4th May 2015 |
| 192.138.32.0/19 | 8.2k | ARIN | US | 1st Apr 1996 |
| 192.138.4.0/22 | 1k | RIPE NCC | GB | 2nd Jan 1992 |
| 192.138.8.0/24 | 256 | RIPE NCC | GB | 2nd Jan 1992 |
| 192.138.84.0/24 | 256 | ARIN | US | 3rd Jan 1992 |
| 192.138.88.0/24 | 256 | ARIN | US | 3rd Jan 1992 |