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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 192.151.81.0/24 | 256 | ARIN |  US | 26th Mar 1992 |
| 192.151.82.0/23 | 512 | ARIN | US | 26th Mar 1992 |
| 192.151.84.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.90.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.91.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.92.0/23 | 512 | ARIN | US | 26th Mar 1992 |
| 192.151.94.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.95.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.96.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.97.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.98.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.151.99.0/24 | 256 | ARIN | US | 26th Mar 1992 |
| 192.152.0.0/24 | 256 | ARIN | US | 6th Apr 2020 |
| 192.152.101.0/24 | 256 | ARIN | US | 11th May 1992 |
| 192.152.102.0/24 | 256 | ARIN | US | 11th May 1992 |
| 192.152.104.0/24 | 256 | ARIN | US | 11th May 1992 |
| 192.152.105.0/24 | 256 | ARIN | US | 11th May 1992 |
| 192.152.108.0/24 | 256 | ARIN | US | 11th May 1992 |
| 192.152.109.0/24 | 256 | ARIN | US | 11th May 1992 |
| 192.152.11.0/24 | 256 | ARIN | US | 31st Mar 1992 |
| 192.152.111.0/24 | 256 | RIPE NCC |  NO | 11th May 1992 |
| 192.152.112.0/24 | 256 | RIPE NCC |  GB | 11th May 1992 |
| 192.152.113.0/24 | 256 | ARIN | US | 11th May 1992 |
| 192.152.116.0/24 | 256 | ARIN | US | 11th May 1992 |
| 192.152.12.0/24 | 256 | ARIN | US | 31st Mar 1992 |
| 192.152.120.0/24 | 256 | ARIN | US | 12th May 1992 |
| 192.152.121.0/24 | 256 | ARIN | US | 13th May 1992 |
| 192.152.122.0/24 | 256 | RIPE NCC | GB | 13th May 1992 |
| 192.152.124.0/24 | 256 | RIPE NCC |  BE | 15th May 1992 |
| 192.152.125.0/24 | 256 | ARIN | US | 6th May 1992 |
| 192.152.127.0/24 | 256 | ARIN | US | 15th May 1992 |
| 192.152.129.0/24 | 256 | ARIN | US | 11th Jun 2015 |
| 192.152.13.0/24 | 256 | ARIN | US | 31st Mar 1992 |
| 192.152.135.0/24 | 256 | ARIN | US | 6th Aug 2015 |
| 192.152.136.0/24 | 256 | ARIN | US | 20th May 1992 |
| 192.152.137.0/24 | 256 | ARIN | US | 20th May 1992 |
| 192.152.139.0/24 | 256 | ARIN | US | 20th May 1992 |
| 192.152.140.0/24 | 256 | ARIN | US | 5th Jun 2023 |
| 192.152.141.0/24 | 256 | RIPE NCC |  IT | 20th May 1992 |
| 192.152.142.0/24 | 256 | ARIN | US | 20th May 1992 |
| 192.152.144.0/24 | 256 | APNIC |  HK | 18th Aug 2026 |
| 192.152.145.0/24 | 256 | ARIN | US | 20th May 1992 |
| 192.152.147.0/24 | 256 | ARIN | US | 20th May 1992 |
| 192.152.151.0/24 | 256 | RIPE NCC |  DE | 20th May 1992 |
| 192.152.154.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.152.155.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.152.156.0/24 | 256 | RIPE NCC | GB | 22nd May 1992 |
| 192.152.159.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.152.16.0/24 | 256 | ARIN | US | 31st Mar 1992 |
| 192.152.160.0/24 | 256 | ARIN | US | 22nd May 1992 |