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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 192.100.28.0/24 | 256 | ARIN |  US | 19th Mar 1991 |
| 192.100.3.0/24 | 256 | ARIN | US | 11th Mar 1991 |
| 192.100.31.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.100.32.0/21 | 2k | ARIN | US | 22nd Mar 1991 |
| 192.100.40.0/22 | 1k | ARIN | US | 22nd Mar 1991 |
| 192.100.44.0/23 | 512 | ARIN | US | 22nd Mar 1991 |
| 192.100.46.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.100.47.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.100.48.0/23 | 512 | ARIN | US | 22nd Mar 1991 |
| 192.100.50.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.100.52.0/24 | 256 | RIPE NCC |  GB | 22nd Mar 1991 |
| 192.100.56.0/24 | 256 | ARIN | US | 25th Mar 1991 |
| 192.100.57.0/24 | 256 | ARIN | US | 26th Mar 1991 |
| 192.100.58.0/24 | 256 | ARIN | US | 26th Mar 1991 |
| 192.100.61.0/24 | 256 | RIPE NCC | GB | 26th Mar 1991 |
| 192.100.62.0/24 | 256 | ARIN | US | 26th Mar 1991 |
| 192.100.63.0/24 | 256 | RIPE NCC |  NO | 28th Mar 1991 |
| 192.100.66.0/24 | 256 | RIPE NCC |  FR | 1st Apr 1991 |
| 192.100.67.0/24 | 256 | ARIN | US | 1st Apr 1991 |
| 192.100.69.0/24 | 256 | ARIN | US | 2nd Apr 1991 |
| 192.100.72.0/22 | 1k | ARIN | US | 28th Aug 2012 |
| 192.100.76.0/24 | 256 | ARIN | US | 3rd Apr 1991 |
| 192.100.79.0/24 | 256 | ARIN | US | 3rd Apr 1991 |
| 192.100.81.0/24 | 256 | ARIN | US | 3rd Apr 1991 |
| 192.100.83.0/24 | 256 | ARIN | US | 8th Apr 1991 |
| 192.100.84.0/23 | 512 | ARIN | US | 8th Apr 1991 |
| 192.100.86.0/24 | 256 | ARIN | US | 8th Apr 1991 |
| 192.100.87.0/24 | 256 | ARIN |  CA | 24th Mar 2015 |
| 192.100.88.0/24 | 256 | ARIN | US | 9th Apr 1991 |
| 192.100.98.0/24 | 256 | RIPE NCC |  DE | 12th Apr 1991 |
| 192.100.99.0/24 | 256 | RIPE NCC | GB | 12th Apr 1991 |
| 192.101.11.0/24 | 256 | RIPE NCC | GB | 28th Mar 1991 |
| 192.101.110.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.114.0/24 | 256 | RIPE NCC |  NL | 27th Jun 1991 |
| 192.101.115.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.116.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.117.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.12.0/24 | 256 | ARIN | US | 28th Mar 1991 |
| 192.101.120.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.121.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.122.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.123.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.124.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.125.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.126.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.127.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.128.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.129.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.13.0/24 | 256 | ARIN | US | 28th Mar 1991 |
| 192.101.130.0/24 | 256 | ARIN | US | 27th Jun 1991 |