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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,392 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 205.151.169.0/24 | 256 | ARIN |  CA | 28th Feb 1995 |
| 205.151.170.0/23 | 512 | ARIN | CA | 28th Feb 1995 |
| 205.151.172.0/22 | 1k | ARIN | CA | 28th Feb 1995 |
| 205.151.176.0/23 | 512 | ARIN | CA | 28th Feb 1995 |
| 205.151.178.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.180.0/22 | 1k | ARIN | CA | 28th Feb 1995 |
| 205.151.184.0/23 | 512 | ARIN | CA | 28th Feb 1995 |
| 205.151.186.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.187.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.188.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.189.0/24 | 256 | ARIN |  US | 13th Apr 2012 |
| 205.151.190.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.191.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.20.0/22 | 1k | ARIN | CA | 21st Apr 1995 |
| 205.151.214.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.215.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.216.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.217.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.218.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.219.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.220.0/23 | 512 | ARIN | CA | 28th Feb 1995 |
| 205.151.225.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.24.0/21 | 2k | ARIN | CA | 21st Apr 1995 |
| 205.151.247.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.248.0/23 | 512 | ARIN | CA | 28th Feb 1995 |
| 205.151.48.0/23 | 512 | ARIN | CA | 21st Apr 1995 |
| 205.151.52.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.53.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.57.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.58.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.59.0/24 | 256 | ARIN | CA | 17th Jan 1997 |
| 205.151.60.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.8.0/21 | 2k | ARIN | CA | 28th Feb 1995 |
| 205.151.80.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.81.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.82.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.83.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.84.0/22 | 1k | ARIN | CA | 28th Feb 1995 |
| 205.151.88.0/21 | 2k | ARIN | CA | 28th Feb 1995 |
| 205.151.96.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.97.0/24 | 256 | ARIN | CA | 28th Feb 1995 |
| 205.151.98.0/23 | 512 | ARIN | CA | 28th Feb 1995 |
| 205.153.0.0/22 | 1k | ARIN | US | 21st Mar 1995 |
| 205.153.12.0/22 | 1k | ARIN | US | 22nd Mar 1995 |
| 205.153.124.0/22 | 1k | ARIN | US | 26th May 1995 |
| 205.153.132.0/22 | 1k | ARIN | US | 30th May 1995 |
| 205.153.136.0/22 | 1k | ARIN | US | 31st May 1995 |
| 205.153.148.0/22 | 1k | ARIN | US | 31st May 1995 |
| 205.153.160.0/22 | 1k | ARIN | US | 5th Jun 1995 |
| 205.153.164.0/22 | 1k | ARIN | US | 5th Jun 1995 |