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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,149 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.231.13.0/24 | 256 | ARIN |  US | 22nd Sept 1992 |
| 192.231.136.0/24 | 256 | APNIC |  AU | 8th Oct 1992 |
| 192.231.138.0/24 | 256 | ARIN | US | 8th Oct 1992 |
| 192.231.139.0/24 | 256 | ARIN | US | 8th Oct 1992 |
| 192.231.14.0/24 | 256 | ARIN | US | 22nd Sept 1992 |
| 192.231.140.0/24 | 256 | LACNIC |  CL | 8th Oct 1992 |
| 192.231.142.0/24 | 256 | ARIN | US | 8th Oct 1992 |
| 192.231.148.0/24 | 256 | ARIN | US | 9th Oct 1992 |
| 192.231.149.0/24 | 256 | ARIN | US | 24th Jul 1996 |
| 192.231.150.0/24 | 256 | ARIN | US | 9th Oct 1992 |
| 192.231.156.0/22 | 1k | ARIN | US | 9th Oct 1992 |
| 192.231.161.0/24 | 256 | ARIN | US | 12th Oct 1992 |
| 192.231.165.0/24 | 256 | ARIN | US | 13th Oct 1992 |
| 192.231.168.0/24 | 256 | APNIC | AU | 13th Oct 1992 |
| 192.231.172.0/24 | 256 | ARIN |  CA | 13th Oct 1992 |
| 192.231.173.0/24 | 256 | ARIN | CA | 13th Oct 1992 |
| 192.231.174.0/24 | 256 | ARIN | CA | 13th Oct 1992 |
| 192.231.18.0/24 | 256 | RIPE NCC |  TR | 22nd Sept 1992 |
| 192.231.180.0/24 | 256 | ARIN | US | 13th Oct 1992 |
| 192.231.181.0/24 | 256 | ARIN | US | 15th Oct 1992 |
| 192.231.182.0/24 | 256 | ARIN | US | 15th Oct 1992 |
| 192.231.183.0/24 | 256 | APNIC |  NZ | 8th Feb 2011 |
| 192.231.184.0/24 | 256 | ARIN | US | 15th Oct 1992 |
| 192.231.185.0/24 | 256 | ARIN | US | 15th Oct 1992 |
| 192.231.186.0/24 | 256 | ARIN | US | 15th Oct 1992 |
| 192.231.187.0/24 | 256 | ARIN | US | 15th Oct 1992 |
| 192.231.189.0/24 | 256 | ARIN | US | 15th Oct 1992 |
| 192.231.19.0/24 | 256 | RIPE NCC | TR | 22nd Sept 1992 |
| 192.231.190.0/24 | 256 | ARIN | US | 15th Oct 1992 |
| 192.231.194.0/24 | 256 | ARIN | US | 15th Oct 1992 |
| 192.231.195.0/24 | 256 | ARIN | US | 16th Oct 1992 |
| 192.231.196.0/24 | 256 | ARIN | US | 16th Oct 1992 |
| 192.231.197.0/24 | 256 | ARIN | US | 16th Oct 1992 |
| 192.231.200.0/24 | 256 | ARIN | US | 16th Oct 1992 |
| 192.231.204.0/24 | 256 | ARIN | US | 16th Oct 1992 |
| 192.231.205.0/24 | 256 | ARIN | US | 16th Oct 1992 |
| 192.231.206.0/24 | 256 | ARIN | US | 16th Oct 1992 |
| 192.231.208.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 192.231.209.0/24 | 256 | ARIN | US | 20th Oct 1992 |
| 192.231.210.0/24 | 256 | ARIN | US | 20th Oct 1992 |
| 192.231.212.0/24 | 256 | APNIC | AU | 20th Oct 1992 |
| 192.231.217.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.22.0/24 | 256 | RIPE NCC | TR | 22nd Sept 1992 |
| 192.231.221.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.222.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.223.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.224.0/22 | 1k | ARIN | US | 22nd Oct 1992 |
| 192.231.228.0/23 | 512 | ARIN | US | 22nd Oct 1992 |
| 192.231.232.0/24 | 256 | ARIN | US | 22nd Oct 1992 |
| 192.231.235.0/24 | 256 | ARIN | US | 22nd Oct 1992 |