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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,001 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 158.180.224.0/23 | 512 | RIPE NCC |  GB | 24th Mar 1992 |
| 158.180.240.0/20 | 4.1k | RIPE NCC |  SE | 24th Mar 1992 |
| 158.180.96.0/19 | 8.2k | RIPE NCC | GB | 24th Mar 1992 |
| 158.183.0.0/16 | 65.5k | ARIN |  US | 25th Mar 1992 |
| 158.184.0.0/23 | 512 | ARIN | US | 25th Mar 1992 |
| 158.184.104.0/22 | 1k | ARIN | US | 25th Mar 1992 |
| 158.184.108.0/23 | 512 | ARIN | US | 25th Mar 1992 |
| 158.184.111.0/24 | 256 | ARIN | US | 25th Mar 1992 |
| 158.184.112.0/20 | 4.1k | ARIN | US | 25th Mar 1992 |
| 158.184.128.0/18 | 16.4k | ARIN | US | 25th Mar 1992 |
| 158.184.16.0/20 | 4.1k | ARIN | US | 25th Mar 1992 |
| 158.184.2.0/24 | 256 | ARIN | US | 25th Mar 1992 |
| 158.184.225.0/24 | 256 | ARIN | US | 25th Mar 1992 |
| 158.184.226.0/23 | 512 | ARIN | US | 25th Mar 1992 |
| 158.184.228.0/24 | 256 | ARIN | US | 25th Mar 1992 |
| 158.184.230.0/23 | 512 | ARIN | US | 25th Mar 1992 |
| 158.184.232.0/21 | 2k | ARIN | US | 25th Mar 1992 |
| 158.184.240.0/20 | 4.1k | ARIN | US | 25th Mar 1992 |
| 158.184.32.0/19 | 8.2k | ARIN | US | 25th Mar 1992 |
| 158.184.4.0/22 | 1k | ARIN | US | 25th Mar 1992 |
| 158.184.64.0/19 | 8.2k | ARIN | US | 25th Mar 1992 |
| 158.184.8.0/21 | 2k | ARIN | US | 25th Mar 1992 |
| 158.184.96.0/21 | 2k | ARIN | US | 25th Mar 1992 |
| 158.185.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 158.186.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 158.187.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 158.188.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 158.189.0.0/16 | 65.5k | ARIN | US | 30th Mar 1992 |
| 158.199.0.0/19 | 8.2k | APNIC |  JP | 25th Jun 1992 |
| 158.201.128.0/18 | 16.4k | APNIC | JP | 25th Jun 1992 |
| 158.201.192.0/20 | 4.1k | APNIC | JP | 25th Jun 1992 |
| 158.204.0.0/16 | 65.5k | APNIC | JP | 26th Jun 1992 |
| 158.206.0.0/16 | 65.5k | APNIC | JP | 26th Jun 1992 |
| 158.209.0.0/16 | 65.5k | APNIC | JP | 26th Jun 1992 |
| 158.21.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |
| 158.211.0.0/16 | 65.5k | APNIC | JP | 26th Jun 1992 |
| 158.212.0.0/15 | 131k | APNIC | JP | 26th Jun 1992 |
| 158.214.0.0/16 | 65.5k | APNIC | JP | 26th Jun 1992 |
| 158.216.0.0/16 | 65.5k | RIPE NCC |  CH | 1st Sept 1993 |
| 158.218.0.0/16 | 65.5k | RIPE NCC | GB | 1st Apr 1992 |
| 158.22.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |
| 158.222.44.0/22 | 1k | ARIN | US | 1st Apr 1992 |
| 158.226.0.0/16 | 65.5k | RIPE NCC |  DE | 3rd Apr 1992 |
| 158.247.48.0/21 | 2k | ARIN | US | 9th Jul 2020 |
| 158.247.62.0/23 | 512 | ARIN | US | 16th May 1991 |
| 158.247.64.0/23 | 512 | ARIN | US | 16th May 1991 |
| 158.247.66.0/23 | 512 | ARIN | US | 9th Jul 2020 |
| 158.25.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |
| 158.255.72.0/24 | 256 | RIPE NCC | DE | 30th Aug 2021 |
| 158.27.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |