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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,285 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 199.166.192.0/23 | 512 | ARIN |  CA | 2nd Feb 1994 |
| 199.166.194.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.195.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.196.0/23 | 512 | ARIN | CA | 2nd Feb 1994 |
| 199.166.2.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.20.0/24 | 256 | ARIN | CA | 26th Apr 1994 |
| 199.166.200.0/22 | 1k | ARIN | CA | 2nd Feb 1994 |
| 199.166.204.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.205.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.208.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.21.0/24 | 256 | ARIN | CA | 16th May 1994 |
| 199.166.211.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.213.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.214.0/23 | 512 | ARIN | CA | 2nd Feb 1994 |
| 199.166.216.0/23 | 512 | ARIN |  US | 2nd Feb 1994 |
| 199.166.218.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 199.166.22.0/24 | 256 | ARIN | CA | 1st Jun 1994 |
| 199.166.220.0/22 | 1k | ARIN | CA | 2nd Feb 1994 |
| 199.166.224.0/23 | 512 | ARIN | CA | 2nd Feb 1994 |
| 199.166.226.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.229.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.23.0/24 | 256 | ARIN | CA | 22nd Jun 1994 |
| 199.166.234.0/23 | 512 | ARIN | CA | 2nd Feb 1994 |
| 199.166.237.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.238.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.239.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.24.0/21 | 2k | ARIN | US | 26th Apr 1994 |
| 199.166.246.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.247.0/24 | 256 | ARIN | CA | 14th May 1994 |
| 199.166.253.0/24 | 256 | ARIN | CA | 4th Jul 1994 |
| 199.166.255.0/24 | 256 | ARIN | US | 9th May 2019 |
| 199.166.38.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.39.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.4.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.166.40.0/21 | 2k | ARIN | CA | 2nd Feb 1994 |
| 199.166.48.0/20 | 4.1k | ARIN | CA | 2nd Feb 1994 |
| 199.166.7.0/24 | 256 | ARIN | CA | 2nd Feb 1994 |
| 199.167.0.0/21 | 2k | ARIN | US | 22nd Apr 1994 |
| 199.167.168.0/22 | 1k | ARIN | US | 8th Jun 2011 |
| 199.167.172.0/22 | 1k | ARIN | US | 8th Jun 2011 |
| 199.167.188.0/23 | 512 | ARIN | US | 17th Dec 2025 |
| 199.167.190.0/24 | 256 | ARIN | US | 17th Dec 2025 |
| 199.167.242.0/24 | 256 | ARIN | US | 16th Jun 2011 |
| 199.168.120.0/22 | 1k | RIPE NCC |  AL | 12th Jun 2019 |
| 199.168.13.0/24 | 256 | ARIN | US | 31st Mar 2009 |
| 199.168.132.0/22 | 1k | ARIN | US | 8th Oct 2025 |
| 199.168.14.0/24 | 256 | ARIN | US | 31st Mar 2009 |
| 199.168.228.0/22 | 1k | ARIN | US | 8th Feb 2022 |
| 199.168.25.0/24 | 256 | ARIN | US | 24th Jul 2012 |
| 199.168.252.0/22 | 1k | ARIN | US | 28th Jun 2011 |