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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,458 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 204.231.192.0/24 | 256 | ARIN |  US | 21st Apr 1995 |
| 204.231.193.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 204.231.194.0/23 | 512 | ARIN | US | 21st Apr 1995 |
| 204.231.196.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 204.231.197.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 204.231.198.0/23 | 512 | ARIN | US | 21st Apr 1995 |
| 204.231.200.0/21 | 2k | ARIN | US | 21st Apr 1995 |
| 204.231.208.0/20 | 4.1k | ARIN | US | 21st Apr 1995 |
| 204.231.224.0/24 | 256 | ARIN |  GB | 21st Apr 1995 |
| 204.231.225.0/24 | 256 | ARIN |  NL | 21st Apr 1995 |
| 204.231.226.0/24 | 256 | ARIN | NL | 21st Apr 1995 |
| 204.231.227.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 204.231.228.0/24 | 256 | ARIN |  DE | 21st Apr 1995 |
| 204.231.230.0/24 | 256 | ARIN |  JP | 21st Apr 1995 |
| 204.231.231.0/24 | 256 | ARIN |  BE | 21st Apr 1995 |
| 204.231.232.0/24 | 256 | ARIN | GB | 21st Apr 1995 |
| 204.231.233.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 204.231.235.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 204.231.236.0/24 | 256 | ARIN | US | 4th May 1995 |
| 204.231.237.0/24 | 256 | ARIN |  IT | 21st Apr 1995 |
| 204.231.239.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 204.231.240.0/24 | 256 | ARIN |  IE | 21st Apr 1995 |
| 204.231.242.0/23 | 512 | ARIN | US | 21st Apr 1995 |
| 204.231.244.0/23 | 512 | ARIN | US | 21st Apr 1995 |
| 204.231.246.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 204.231.247.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 204.231.248.0/23 | 512 | ARIN | US | 21st Apr 1995 |
| 204.231.250.0/24 | 256 | ARIN | US | 21st Apr 1995 |
| 204.231.251.0/24 | 256 | ARIN | JP | 21st Apr 1995 |
| 204.231.252.0/24 | 256 | ARIN | JP | 21st Apr 1995 |
| 204.231.253.0/24 | 256 | ARIN | GB | 4th May 1995 |
| 204.231.254.0/24 | 256 | ARIN | US | 4th May 1995 |
| 204.231.255.0/24 | 256 | ARIN | IE | 4th May 1995 |
| 204.232.0.0/18 | 16.4k | ARIN | US | 17th Jan 1995 |
| 204.235.0.0/20 | 4.1k | ARIN | US | 20th Jan 1995 |
| 204.235.108.0/22 | 1k | ARIN | US | 17th Feb 2009 |
| 204.235.124.0/22 | 1k | ARIN | US | 17th Feb 2009 |
| 204.235.128.0/21 | 2k | ARIN | US | 2nd Feb 1995 |
| 204.235.136.0/22 | 1k | ARIN | US | 2nd Feb 1995 |
| 204.235.140.0/23 | 512 | ARIN | US | 2nd Feb 1995 |
| 204.235.16.0/20 | 4.1k | ARIN | US | 20th Jan 1995 |
| 204.235.174.0/23 | 512 | ARIN | US | 3rd Feb 1995 |
| 204.238.0.0/24 | 256 | ARIN | US | 9th Feb 1995 |
| 204.238.1.0/24 | 256 | ARIN | US | 9th Feb 1995 |
| 204.238.10.0/24 | 256 | ARIN | US | 9th Feb 1995 |
| 204.238.100.0/24 | 256 | ARIN | US | 2nd May 1995 |
| 204.238.102.0/24 | 256 | ARIN | US | 2nd May 1995 |
| 204.238.103.0/24 | 256 | ARIN | US | 2nd May 1995 |
| 204.238.105.0/24 | 256 | ARIN | US | 5th May 1995 |
| 204.238.106.0/24 | 256 | ARIN | US | 5th May 1995 |