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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 192.104.249.0/24 | 256 | ARIN |  US | 21st Jun 1991 |
| 192.104.25.0/24 | 256 | ARIN | US | 9th Apr 1991 |
| 192.104.250.0/24 | 256 | ARIN | US | 21st Jun 1991 |
| 192.104.251.0/24 | 256 | RIPE NCC |  CH | 21st Jun 1991 |
| 192.104.253.0/24 | 256 | ARIN | US | 21st Jun 1991 |
| 192.104.27.0/24 | 256 | ARIN | US | 2nd Apr 1991 |
| 192.104.28.0/24 | 256 | RIPE NCC |  GB | 9th Apr 1991 |
| 192.104.29.0/24 | 256 | RIPE NCC | GB | 9th Apr 1991 |
| 192.104.30.0/24 | 256 | ARIN | US | 9th Apr 1991 |
| 192.104.32.0/24 | 256 | ARIN | US | 9th Apr 1991 |
| 192.104.33.0/24 | 256 | ARIN | US | 9th Apr 1991 |
| 192.104.35.0/24 | 256 | RIPE NCC |  PT | 11th Apr 1991 |
| 192.104.38.0/24 | 256 | ARIN |  CA | 28th Mar 2018 |
| 192.104.46.0/24 | 256 | ARIN | US | 18th Apr 1991 |
| 192.104.47.0/24 | 256 | ARIN | US | 18th Apr 1991 |
| 192.104.50.0/24 | 256 | ARIN | US | 24th Apr 1991 |
| 192.104.51.0/24 | 256 | ARIN | US | 24th Apr 1991 |
| 192.104.52.0/24 | 256 | ARIN | US | 24th Apr 1991 |
| 192.104.53.0/24 | 256 | RIPE NCC | GB | 30th Apr 1991 |
| 192.104.55.0/24 | 256 | RIPE NCC |  NL | 30th Apr 1991 |
| 192.104.56.0/24 | 256 | RIPE NCC | NL | 30th Apr 1991 |
| 192.104.57.0/24 | 256 | RIPE NCC |  NO | 30th Jun 1991 |
| 192.104.58.0/24 | 256 | RIPE NCC | NO | 30th Apr 1991 |
| 192.104.59.0/24 | 256 | ARIN | US | 30th Apr 1991 |
| 192.104.6.0/24 | 256 | ARIN | US | 20th Mar 1991 |
| 192.104.60.0/24 | 256 | ARIN | US | 2nd May 1991 |
| 192.104.62.0/24 | 256 | ARIN | US | 2nd May 1991 |
| 192.104.63.0/24 | 256 | ARIN | US | 2nd May 1991 |
| 192.104.64.0/24 | 256 | ARIN | US | 2nd May 1991 |
| 192.104.65.0/24 | 256 | ARIN | US | 2nd May 1991 |
| 192.104.66.0/24 | 256 | ARIN | US | 9th May 1991 |
| 192.104.68.0/24 | 256 | ARIN | US | 9th May 1991 |
| 192.104.69.0/24 | 256 | ARIN | US | 9th May 1991 |
| 192.104.7.0/24 | 256 | ARIN | US | 20th Mar 1991 |
| 192.104.70.0/24 | 256 | ARIN | US | 9th May 1991 |
| 192.104.71.0/24 | 256 | ARIN | US | 9th May 1991 |
| 192.104.72.0/24 | 256 | RIPE NCC | CH | 9th May 1991 |
| 192.104.74.0/24 | 256 | ARIN | US | 9th May 1991 |
| 192.104.75.0/24 | 256 | ARIN | US | 9th May 1991 |
| 192.104.76.0/24 | 256 | ARIN | US | 13th May 1991 |
| 192.104.78.0/24 | 256 | ARIN | US | 16th May 1991 |
| 192.104.79.0/24 | 256 | ARIN | US | 16th May 1991 |
| 192.104.8.0/24 | 256 | ARIN | US | 20th Mar 1991 |
| 192.104.81.0/24 | 256 | ARIN | US | 16th May 1991 |
| 192.104.82.0/24 | 256 | RIPE NCC | GB | 16th May 1991 |
| 192.104.83.0/24 | 256 | ARIN | US | 16th May 1991 |
| 192.104.84.0/24 | 256 | ARIN | US | 16th May 1991 |
| 192.104.85.0/24 | 256 | ARIN | US | 16th May 1991 |
| 192.104.86.0/24 | 256 | ARIN | US | 16th May 1991 |
| 192.104.87.0/24 | 256 | ARIN | US | 16th May 1991 |