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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,201 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.25.197.0/24 | 256 | ARIN |  US | 8th Aug 1986 |
| 192.25.198.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.199.0/24 | 256 | ARIN | US | 2nd Mar 2000 |
| 192.25.20.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.212.0/22 | 1k | ARIN | US | 8th Aug 1986 |
| 192.25.219.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.220.0/22 | 1k | ARIN | US | 8th Aug 1986 |
| 192.25.224.0/22 | 1k | ARIN | US | 8th Aug 1986 |
| 192.25.228.0/23 | 512 | ARIN | US | 8th Aug 1986 |
| 192.25.23.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.231.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.241.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.242.0/23 | 512 | ARIN | US | 8th Aug 1986 |
| 192.25.248.0/21 | 2k | ARIN | US | 8th Aug 1986 |
| 192.25.25.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.26.0/23 | 512 | ARIN | US | 8th Aug 1986 |
| 192.25.28.0/24 | 256 | ARIN | US | 2nd Mar 2000 |
| 192.25.29.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.30.0/23 | 512 | ARIN | US | 24th Feb 2001 |
| 192.25.32.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.33.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.35.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.36.0/22 | 1k | ARIN | US | 8th Aug 1986 |
| 192.25.40.0/23 | 512 | ARIN | US | 8th Aug 1986 |
| 192.25.43.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.44.0/23 | 512 | ARIN | US | 8th Aug 1986 |
| 192.25.47.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.48.0/24 | 256 | ARIN | US | 2nd Mar 2000 |
| 192.25.49.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.51.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.53.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.54.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.64.0/22 | 1k | ARIN | US | 8th Aug 1986 |
| 192.25.68.0/23 | 512 | ARIN | US | 28th Feb 2001 |
| 192.25.70.0/24 | 256 | ARIN | US | 28th Feb 2001 |
| 192.25.71.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.72.0/23 | 512 | ARIN | US | 8th Aug 1986 |
| 192.25.74.0/24 | 256 | ARIN | US | 2nd Mar 2000 |
| 192.25.75.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.76.0/23 | 512 | ARIN | US | 8th Aug 1986 |
| 192.25.79.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.80.0/24 | 256 | ARIN | US | 8th Aug 1986 |
| 192.25.81.0/24 | 256 | ARIN | US | 2nd Mar 2000 |
| 192.25.82.0/23 | 512 | ARIN | US | 2nd Mar 2000 |
| 192.25.84.0/22 | 1k | ARIN | US | 2nd Mar 2000 |
| 192.25.96.0/22 | 1k | ARIN | US | 2nd Mar 2000 |
| 192.250.208.0/20 | 4.1k | ARIN | US | 4th Jun 2013 |
| 192.251.10.0/24 | 256 | ARIN | US | 9th Nov 1992 |
| 192.251.100.0/24 | 256 | ARIN | US | 27th Nov 1992 |
| 192.251.106.0/24 | 256 | ARIN | US | 6th Oct 2025 |