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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,201 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.42.77.0/24 | 256 | ARIN |  US | 29th Aug 1988 |
| 192.42.78.0/24 | 256 | ARIN | US | 29th Aug 1988 |
| 192.42.79.0/24 | 256 | ARIN | US | 29th Aug 1988 |
| 192.42.8.0/24 | 256 | ARIN | US | 5th Aug 1988 |
| 192.42.87.0/24 | 256 | RIPE NCC |  GB | 2nd Sept 1988 |
| 192.42.9.0/24 | 256 | ARIN | US | 8th Aug 1988 |
| 192.42.90.0/24 | 256 | ARIN |  CA | 9th Sept 1988 |
| 192.42.91.0/24 | 256 | ARIN | US | 9th Sept 1988 |
| 192.42.94.0/24 | 256 | ARIN | US | 13th Sept 1988 |
| 192.42.96.0/24 | 256 | ARIN | US | 17th Jul 2014 |
| 192.43.1.0/24 | 256 | ARIN | US | 4th Oct 1988 |
| 192.43.128.0/20 | 4.1k | ARIN | US | 4th Oct 1988 |
| 192.43.144.0/22 | 1k | ARIN | US | 4th Oct 1988 |
| 192.43.148.0/23 | 512 | ARIN | US | 4th Oct 1988 |
| 192.43.150.0/24 | 256 | ARIN | US | 4th Oct 1988 |
| 192.43.151.0/24 | 256 | ARIN | US | 20th Oct 1988 |
| 192.43.16.0/20 | 4.1k | ARIN | US | 4th Oct 1988 |
| 192.43.162.0/23 | 512 | RIPE NCC |  SE | 15th Nov 1988 |
| 192.43.173.0/24 | 256 | ARIN | US | 7th Aug 1991 |
| 192.43.188.0/24 | 256 | ARIN | US | 21st Nov 1988 |
| 192.43.189.0/24 | 256 | APNIC |  JP | 11th Feb 2011 |
| 192.43.190.0/24 | 256 | ARIN | CA | 28th Jul 2014 |
| 192.43.191.0/24 | 256 | ARIN | US | 28th Nov 1988 |
| 192.43.199.0/24 | 256 | ARIN | US | 29th Nov 1988 |
| 192.43.2.0/23 | 512 | ARIN | US | 4th Oct 1988 |
| 192.43.200.0/24 | 256 | ARIN | US | 2nd Dec 1988 |
| 192.43.203.0/24 | 256 | ARIN | US | 5th Dec 1988 |
| 192.43.204.0/24 | 256 | ARIN | US | 5th Dec 1988 |
| 192.43.208.0/24 | 256 | APNIC |  AU | 5th Dec 1988 |
| 192.43.211.0/24 | 256 | ARIN | US | 6th Dec 1988 |
| 192.43.213.0/24 | 256 | ARIN | US | 6th Dec 1988 |
| 192.43.214.0/24 | 256 | ARIN | US | 6th Dec 1988 |
| 192.43.216.0/24 | 256 | ARIN | US | 6th Dec 1988 |
| 192.43.218.0/24 | 256 | ARIN | US | 13th Dec 1988 |
| 192.43.220.0/24 | 256 | ARIN | US | 13th Dec 1988 |
| 192.43.222.0/24 | 256 | ARIN | US | 13th Dec 1988 |
| 192.43.229.0/24 | 256 | APNIC | AU | 16th Dec 1988 |
| 192.43.235.0/24 | 256 | ARIN | US | 19th Dec 1988 |
| 192.43.236.0/24 | 256 | ARIN | US | 19th Dec 1988 |
| 192.43.237.0/24 | 256 | ARIN | US | 20th Dec 1988 |
| 192.43.240.0/24 | 256 | ARIN | US | 21st Dec 1988 |
| 192.43.241.0/24 | 256 | ARIN | US | 21st Dec 1988 |
| 192.43.243.0/24 | 256 | ARIN | US | 22nd Dec 1988 |
| 192.43.245.0/24 | 256 | ARIN | US | 23rd Dec 1988 |
| 192.43.247.0/24 | 256 | ARIN | US | 3rd Jan 1989 |
| 192.43.250.0/24 | 256 | ARIN | US | 9th Jan 1989 |
| 192.43.251.0/24 | 256 | ARIN | US | 10th Jan 1989 |
| 192.43.4.0/22 | 1k | ARIN | US | 4th Oct 1988 |
| 192.43.8.0/21 | 2k | ARIN | US | 4th Oct 1988 |
| 192.44.254.0/24 | 256 | ARIN | US | 11th Feb 1998 |