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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 192.161.18.0/24 | 256 | ARIN |  US | 24th Apr 1992 |
| 192.161.19.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.20.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.21.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.22.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.23.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.24.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.25.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.26.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.27.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.28.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.29.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.30.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.31.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.32.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.33.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.34.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.35.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.36.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.37.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.40.0/21 | 2k | ARIN | US | 15th Feb 2013 |
| 192.161.5.0/24 | 256 | ARIN | US | 13th Jul 2015 |
| 192.161.64.0/24 | 256 | RIPE NCC |  BE | 27th Apr 1992 |
| 192.161.65.0/24 | 256 | RIPE NCC | BE | 27th Apr 1992 |
| 192.161.8.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.161.9.0/24 | 256 | ARIN | US | 24th Apr 1992 |
| 192.162.176.0/22 | 1k | RIPE NCC |  PL | 6th Apr 2011 |
| 192.162.18.0/24 | 256 | RIPE NCC |  GB | 25th Mar 2011 |
| 192.163.1.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.10.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.12.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.13.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.16.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.18.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.19.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.2.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.20.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.24.0/22 | 1k | ARIN |  MQ | 5th Jul 2023 |
| 192.163.3.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.4.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.6.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.7.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.8.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.163.9.0/24 | 256 | ARIN | US | 8th May 1992 |
| 192.164.168.0/22 | 1k | RIPE NCC |  AT | 1st Sept 1993 |
| 192.164.36.0/23 | 512 | RIPE NCC | AT | 1st Sept 1993 |
| 192.166.128.0/22 | 1k | RIPE NCC |  UA | 7th Mar 2011 |
| 192.166.140.0/22 | 1k | RIPE NCC |  FR | 10th Mar 2011 |
| 192.166.152.0/24 | 256 | RIPE NCC |  DE | 7th May 1992 |
| 192.166.158.0/24 | 256 | RIPE NCC | DE | 7th May 1992 |