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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 192.103.8.0/24 | 256 | ARIN |  US | 21st Jun 1991 |
| 192.103.81.0/24 | 256 | ARIN | US | 12th Jul 1991 |
| 192.103.82.0/24 | 256 | ARIN | US | 13th Jul 1991 |
| 192.103.83.0/24 | 256 | ARIN | US | 13th Jul 1991 |
| 192.103.9.0/24 | 256 | ARIN | US | 20th Jun 1991 |
| 192.104.104.0/23 | 512 | ARIN | US | 16th May 1991 |
| 192.104.106.0/24 | 256 | ARIN | US | 16th May 1991 |
| 192.104.12.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.104.138.0/24 | 256 | ARIN | US | 22nd May 1991 |
| 192.104.14.0/24 | 256 | ARIN | US | 28th Mar 1991 |
| 192.104.142.0/24 | 256 | RIPE NCC |  NL | 23rd May 1991 |
| 192.104.143.0/24 | 256 | ARIN | US | 23rd May 1991 |
| 192.104.144.0/24 | 256 | ARIN | US | 23rd May 1991 |
| 192.104.145.0/24 | 256 | ARIN | US | 23rd May 1991 |
| 192.104.146.0/24 | 256 | ARIN | US | 23rd May 1991 |
| 192.104.149.0/24 | 256 | ARIN | US | 23rd May 1991 |
| 192.104.150.0/24 | 256 | ARIN | US | 23rd May 1991 |
| 192.104.152.0/24 | 256 | ARIN | US | 30th May 1991 |
| 192.104.154.0/24 | 256 | RIPE NCC |  IE | 30th May 1991 |
| 192.104.155.0/24 | 256 | RIPE NCC |  FR | 11th Jun 1991 |
| 192.104.156.0/24 | 256 | ARIN | US | 4th Mar 1996 |
| 192.104.159.0/24 | 256 | ARIN | US | 12th Mar 2015 |
| 192.104.16.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.104.163.0/24 | 256 | ARIN | US | 5th Jun 1991 |
| 192.104.164.0/24 | 256 | ARIN | US | 5th Jun 1991 |
| 192.104.165.0/24 | 256 | ARIN | US | 5th Jun 1991 |
| 192.104.167.0/24 | 256 | RIPE NCC |  BE | 11th Jun 1991 |
| 192.104.168.0/24 | 256 | RIPE NCC | BE | 11th Jun 1991 |
| 192.104.17.0/24 | 256 | ARIN | US | 28th Mar 1991 |
| 192.104.171.0/24 | 256 | ARIN | US | 11th Jun 1991 |
| 192.104.172.0/24 | 256 | APNIC |  JP | 11th Jun 1991 |
| 192.104.173.0/24 | 256 | ARIN | US | 11th Jun 1991 |
| 192.104.175.0/24 | 256 | ARIN | US | 11th Jun 1991 |
| 192.104.176.0/22 | 1k | ARIN | US | 11th Jun 1991 |
| 192.104.18.0/24 | 256 | ARIN | US | 28th Mar 1991 |
| 192.104.180.0/24 | 256 | ARIN | US | 11th Jun 1991 |
| 192.104.19.0/24 | 256 | ARIN | US | 28th Mar 1991 |
| 192.104.2.0/24 | 256 | ARIN | US | 20th Mar 1991 |
| 192.104.21.0/24 | 256 | ARIN | US | 28th Mar 1991 |
| 192.104.22.0/24 | 256 | ARIN | US | 2nd Apr 1991 |
| 192.104.235.0/24 | 256 | ARIN | US | 17th Jun 1991 |
| 192.104.236.0/24 | 256 | ARIN | US | 17th Jun 1991 |
| 192.104.238.0/24 | 256 | RIPE NCC |  GB | 17th Jun 1991 |
| 192.104.239.0/24 | 256 | ARIN | US | 17th Jun 1991 |
| 192.104.240.0/24 | 256 | ARIN | US | 19th Mar 1993 |
| 192.104.241.0/24 | 256 | ARIN | US | 17th Jun 1991 |
| 192.104.244.0/24 | 256 | ARIN | US | 17th Jun 1991 |
| 192.104.245.0/24 | 256 | RIPE NCC | FR | 17th Jun 1991 |
| 192.104.247.0/24 | 256 | APNIC | JP | 17th Jun 1991 |
| 192.104.248.0/24 | 256 | RIPE NCC |  DK | 20th Jun 1991 |