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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 in United States
26,993 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 158.118.0.0/16 | 65.5k | ARIN |  US | 27th Feb 1992 |
| 158.120.78.0/24 | 256 | ARIN | US | 14th Feb 2023 |
| 158.120.79.0/24 | 256 | RIPE NCC | US | 28th Feb 1992 |
| 158.134.0.0/16 | 65.5k | ARIN | US | 9th Mar 1992 |
| 158.137.0.0/16 | 65.5k | ARIN | US | 6th Mar 1992 |
| 158.139.0.0/16 | 65.5k | ARIN | US | 10th Mar 1992 |
| 158.140.8.0/21 | 2k | ARIN | US | 1st Jun 2016 |
| 158.146.160.0/19 | 8.2k | ARIN | US | 12th Mar 1992 |
| 158.146.192.0/18 | 16.4k | ARIN | US | 12th Mar 1992 |
| 158.159.0.0/16 | 65.5k | ARIN | US | 17th Mar 1992 |
| 158.164.0.0/16 | 65.5k | ARIN | US | 18th Mar 1992 |
| 158.171.0.0/16 | 65.5k | ARIN | US | 23rd Mar 1992 |
| 158.178.0.0/17 | 32.8k | RIPE NCC | US | 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 |
| 158.21.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |
| 158.22.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |
| 158.222.44.0/22 | 1k | ARIN | US | 1st Apr 1992 |
| 158.247.48.0/21 | 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 |
| 158.27.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |
| 158.29.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |
| 158.30.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |
| 158.31.0.0/16 | 65.5k | ARIN | US | 7th Feb 1992 |