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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
27,007 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 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 |
| 192.152.113.0/24 | 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 |
| 192.152.125.0/24 | 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 |
| 192.152.142.0/24 | 256 | ARIN | US | 20th May 1992 |
| 192.152.145.0/24 | 256 | ARIN | US | 20th May 1992 |
| 192.152.147.0/24 | 256 | ARIN | US | 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 |
| 192.152.159.0/24 | 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 |
| 192.152.162.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.152.163.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.152.169.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.152.175.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.152.176.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.152.177.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.152.178.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.152.179.0/24 | 256 | ARIN | US | 28th May 1992 |
| 192.152.182.0/24 | 256 | ARIN | US | 1st Jun 1992 |