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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 192.101.131.0/24 | 256 | ARIN |  US | 27th Jun 1991 |
| 192.101.134.0/24 | 256 | APNIC |  AU | 27th Jun 1991 |
| 192.101.137.0/24 | 256 | RIPE NCC |  GB | 27th Jun 1991 |
| 192.101.138.0/24 | 256 | ARIN | US | 6th Mar 2015 |
| 192.101.14.0/24 | 256 | ARIN | US | 28th Mar 1991 |
| 192.101.141.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 192.101.142.0/24 | 256 | AFRINIC |  EG | 5th Jul 1991 |
| 192.101.144.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 192.101.146.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 192.101.147.0/24 | 256 | ARIN | US | 3rd Jan 1992 |
| 192.101.148.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 192.101.149.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 192.101.15.0/24 | 256 | ARIN | US | 28th Mar 1991 |
| 192.101.150.0/23 | 512 | ARIN |  CA | 19th Nov 2015 |
| 192.101.152.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 192.101.153.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 192.101.154.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 192.101.155.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 192.101.157.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 192.101.158.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 192.101.159.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 192.101.16.0/24 | 256 | APNIC |  NZ | 16th Apr 1991 |
| 192.101.169.0/24 | 256 | ARIN |  PR | 11th Jul 1991 |
| 192.101.17.0/24 | 256 | ARIN | US | 16th Apr 1991 |
| 192.101.170.0/24 | 256 | RIPE NCC |  BE | 11th Jul 1991 |
| 192.101.171.0/24 | 256 | ARIN | US | 11th Jul 1991 |
| 192.101.173.0/24 | 256 | ARIN | US | 12th Sept 1991 |
| 192.101.175.0/24 | 256 | ARIN | US | 12th Jul 1991 |
| 192.101.178.0/24 | 256 | ARIN | US | 16th Jul 1991 |
| 192.101.179.0/24 | 256 | RIPE NCC |  DE | 16th Jul 1991 |
| 192.101.180.0/24 | 256 | RIPE NCC | DE | 16th Jul 1991 |
| 192.101.181.0/24 | 256 | ARIN | US | 16th Jul 1991 |
| 192.101.182.0/24 | 256 | ARIN | US | 16th Jul 1991 |
| 192.101.184.0/24 | 256 | ARIN | US | 16th Jul 1991 |
| 192.101.187.0/24 | 256 | ARIN | US | 16th Jul 1991 |
| 192.101.189.0/24 | 256 | ARIN | US | 16th Jul 1991 |
| 192.101.19.0/24 | 256 | ARIN | US | 16th Apr 1991 |
| 192.101.191.0/24 | 256 | ARIN | US | 19th Jul 1991 |
| 192.101.192.0/24 | 256 | RIPE NCC |  FI | 19th Jul 1991 |
| 192.101.193.0/24 | 256 | ARIN | US | 19th Jul 1991 |
| 192.101.194.0/24 | 256 | ARIN | US | 19th Jul 1991 |
| 192.101.195.0/24 | 256 | ARIN | US | 19th Jul 1991 |
| 192.101.196.0/24 | 256 | ARIN | US | 19th Jul 1991 |
| 192.101.197.0/24 | 256 | RIPE NCC | DE | 19th Jul 1991 |
| 192.101.198.0/24 | 256 | RIPE NCC | DE | 19th Jul 1991 |
| 192.101.199.0/24 | 256 | ARIN | US | 18th Mar 2015 |
| 192.101.2.0/24 | 256 | ARIN | US | 11th Mar 1991 |
| 192.101.20.0/24 | 256 | ARIN | US | 16th Apr 1991 |
| 192.101.200.0/21 | 2k | ARIN | US | 19th Jul 1991 |
| 192.101.208.0/20 | 4.1k | ARIN | US | 19th Jul 1991 |