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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 192.101.224.0/20 | 4.1k | ARIN |  US | 19th Jul 1991 |
| 192.101.240.0/21 | 2k | ARIN | US | 19th Jul 1991 |
| 192.101.248.0/23 | 512 | ARIN | US | 19th Jul 1991 |
| 192.101.25.0/24 | 256 | ARIN | US | 17th Apr 1991 |
| 192.101.253.0/24 | 256 | ARIN | US | 19th Jul 1991 |
| 192.101.26.0/24 | 256 | ARIN | US | 25th Apr 1991 |
| 192.101.27.0/24 | 256 | ARIN | US | 25th Apr 1991 |
| 192.101.28.0/24 | 256 | RIPE NCC |  DE | 25th Apr 1991 |
| 192.101.29.0/24 | 256 | ARIN | US | 25th Apr 1991 |
| 192.101.3.0/24 | 256 | ARIN | US | 11th Mar 1991 |
| 192.101.30.0/24 | 256 | ARIN | US | 25th Apr 1991 |
| 192.101.31.0/24 | 256 | ARIN | US | 25th Apr 1991 |
| 192.101.34.0/24 | 256 | RIPE NCC |  GB | 18th Jun 1991 |
| 192.101.35.0/24 | 256 | ARIN | US | 18th Jun 1991 |
| 192.101.36.0/24 | 256 | ARIN | US | 18th Jun 1991 |
| 192.101.37.0/24 | 256 | ARIN | US | 18th Jun 1991 |
| 192.101.38.0/24 | 256 | ARIN | US | 18th Jun 1991 |
| 192.101.39.0/24 | 256 | ARIN | US | 18th Jun 1991 |
| 192.101.4.0/24 | 256 | RIPE NCC |  RU | 11th Mar 1991 |
| 192.101.40.0/24 | 256 | ARIN | US | 18th Jun 1991 |
| 192.101.41.0/24 | 256 | ARIN | US | 18th Jun 1991 |
| 192.101.44.0/24 | 256 | ARIN | US | 21st Jun 1991 |
| 192.101.45.0/24 | 256 | ARIN | US | 20th Mar 2015 |
| 192.101.6.0/24 | 256 | ARIN | US | 11th Mar 1991 |
| 192.101.7.0/24 | 256 | ARIN | US | 11th Mar 1991 |
| 192.101.76.0/24 | 256 | ARIN | US | 21st Jun 1991 |
| 192.101.78.0/24 | 256 | ARIN | US | 21st Jun 1991 |
| 192.101.79.0/24 | 256 | ARIN | US | 26th Feb 2015 |
| 192.101.8.0/24 | 256 | RIPE NCC |  ES | 11th Mar 1991 |
| 192.101.81.0/24 | 256 | RIPE NCC |  NL | 21st Jun 1991 |
| 192.101.82.0/24 | 256 | RIPE NCC | NL | 21st Jun 1991 |
| 192.101.83.0/24 | 256 | RIPE NCC | NL | 21st Jun 1991 |
| 192.101.88.0/24 | 256 | RIPE NCC | NL | 21st Jun 1991 |
| 192.101.90.0/24 | 256 | RIPE NCC | NL | 21st Jun 1991 |
| 192.101.92.0/24 | 256 | ARIN | US | 21st Jun 1991 |
| 192.101.93.0/24 | 256 | ARIN | US | 21st Jun 1991 |
| 192.101.94.0/24 | 256 | ARIN | US | 21st Jun 1991 |
| 192.101.98.0/24 | 256 | ARIN | US | 13th Nov 2023 |
| 192.101.99.0/24 | 256 | ARIN |  CA | 27th Jun 1991 |
| 192.102.1.0/24 | 256 | RIPE NCC |  AT | 8th Mar 1991 |
| 192.102.10.0/24 | 256 | ARIN | US | 8th Mar 1991 |
| 192.102.12.0/24 | 256 | ARIN | US | 8th Mar 1991 |
| 192.102.14.0/24 | 256 | ARIN | US | 8th Mar 1991 |
| 192.102.178.0/24 | 256 | ARIN | US | 9th Apr 1991 |
| 192.102.179.0/24 | 256 | ARIN | US | 9th Apr 1991 |
| 192.102.18.0/23 | 512 | RIPE NCC |  FI | 8th Mar 1991 |
| 192.102.180.0/24 | 256 | ARIN | US | 7th Aug 1991 |
| 192.102.181.0/24 | 256 | ARIN | US | 9th Apr 1991 |
| 192.102.182.0/24 | 256 | ARIN | US | 11th Apr 1991 |
| 192.102.183.0/24 | 256 | ARIN | US | 11th Apr 1991 |