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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks registered through ARIN
30,434 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.100.12.0/24 | 256 | ARIN |  US | 12th Mar 1991 |
| 192.100.13.0/24 | 256 | ARIN | US | 12th Mar 1991 |
| 192.100.141.0/24 | 256 | ARIN | US | 15th Apr 1991 |
| 192.100.142.0/24 | 256 | ARIN | US | 15th Apr 1991 |
| 192.100.145.0/24 | 256 | ARIN | US | 17th Apr 1991 |
| 192.100.146.0/24 | 256 | ARIN | US | 17th Apr 1991 |
| 192.100.147.0/24 | 256 | ARIN | US | 22nd Apr 1991 |
| 192.100.15.0/24 | 256 | ARIN | US | 12th Mar 1991 |
| 192.100.17.0/24 | 256 | ARIN | US | 13th Mar 1991 |
| 192.100.19.0/24 | 256 | ARIN | US | 14th Mar 1991 |
| 192.100.20.0/24 | 256 | ARIN | US | 14th Mar 1991 |
| 192.100.21.0/24 | 256 | ARIN | US | 14th Mar 1991 |
| 192.100.26.0/24 | 256 | ARIN | US | 18th Mar 1991 |
| 192.100.27.0/24 | 256 | ARIN | US | 19th Mar 1991 |
| 192.100.28.0/24 | 256 | ARIN | US | 19th Mar 1991 |
| 192.100.3.0/24 | 256 | ARIN | US | 11th Mar 1991 |
| 192.100.31.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.100.32.0/21 | 2k | ARIN | US | 22nd Mar 1991 |
| 192.100.40.0/22 | 1k | ARIN | US | 22nd Mar 1991 |
| 192.100.44.0/23 | 512 | ARIN | US | 22nd Mar 1991 |
| 192.100.46.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.100.47.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.100.48.0/23 | 512 | ARIN | US | 22nd Mar 1991 |
| 192.100.50.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.100.56.0/24 | 256 | ARIN | US | 25th Mar 1991 |
| 192.100.57.0/24 | 256 | ARIN | US | 26th Mar 1991 |
| 192.100.58.0/24 | 256 | ARIN | US | 26th Mar 1991 |
| 192.100.62.0/24 | 256 | ARIN | US | 26th Mar 1991 |
| 192.100.67.0/24 | 256 | ARIN | US | 1st Apr 1991 |
| 192.100.69.0/24 | 256 | ARIN | US | 2nd Apr 1991 |
| 192.100.72.0/22 | 1k | ARIN | US | 28th Aug 2012 |
| 192.100.76.0/24 | 256 | ARIN | US | 3rd Apr 1991 |
| 192.100.79.0/24 | 256 | ARIN | US | 3rd Apr 1991 |
| 192.100.81.0/24 | 256 | ARIN | US | 3rd Apr 1991 |
| 192.100.83.0/24 | 256 | ARIN | US | 8th Apr 1991 |
| 192.100.84.0/23 | 512 | ARIN | US | 8th Apr 1991 |
| 192.100.86.0/24 | 256 | ARIN | US | 8th Apr 1991 |
| 192.100.87.0/24 | 256 | ARIN |  CA | 24th Mar 2015 |
| 192.100.88.0/24 | 256 | ARIN | US | 9th Apr 1991 |
| 192.101.110.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.115.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.116.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.117.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.12.0/24 | 256 | ARIN | US | 28th Mar 1991 |
| 192.101.120.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.121.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.122.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.123.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.124.0/24 | 256 | ARIN | US | 27th Jun 1991 |
| 192.101.125.0/24 | 256 | ARIN | US | 27th Jun 1991 |