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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
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Countries with the most unannounced blocks, largest first.
Unannounced blocks
85,458 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 204.145.231.0/24 | 256 | ARIN |  US | 23rd Jan 1995 |
| 204.145.233.0/24 | 256 | ARIN | US | 23rd Jan 1995 |
| 204.145.234.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 204.145.235.0/24 | 256 | ARIN | US | 23rd Jan 1995 |
| 204.145.236.0/24 | 256 | ARIN | US | 23rd Jan 1995 |
| 204.145.238.0/24 | 256 | ARIN | US | 23rd Jan 1995 |
| 204.145.239.0/24 | 256 | ARIN | US | 24th Jan 1995 |
| 204.145.240.0/24 | 256 | ARIN | US | 24th Jan 1995 |
| 204.145.242.0/24 | 256 | ARIN | US | 24th Jan 1995 |
| 204.145.243.0/24 | 256 | ARIN | US | 24th Jan 1995 |
| 204.145.246.0/23 | 512 | ARIN | US | 24th Jan 1995 |
| 204.145.248.0/23 | 512 | ARIN | US | 24th Jan 1995 |
| 204.145.250.0/24 | 256 | ARIN | US | 27th Jan 1995 |
| 204.145.251.0/24 | 256 | ARIN | US | 27th Jan 1995 |
| 204.145.252.0/23 | 512 | ARIN | US | 30th Jan 1995 |
| 204.145.254.0/24 | 256 | ARIN | US | 30th Jan 1995 |
| 204.147.128.0/20 | 4.1k | ARIN | US | 13th Dec 1994 |
| 204.147.192.0/21 | 2k | ARIN | US | 12th Jan 1995 |
| 204.147.200.0/23 | 512 | ARIN | US | 12th Jan 1995 |
| 204.147.240.0/20 | 4.1k | ARIN | US | 17th Jan 1995 |
| 204.147.64.0/21 | 2k | ARIN | US | 25th Nov 1994 |
| 204.147.72.0/22 | 1k | ARIN | US | 25th Nov 1994 |
| 204.147.96.0/20 | 4.1k | ARIN | US | 9th Dec 1994 |
| 204.15.16.0/22 | 1k | ARIN | US | 2nd Aug 2005 |
| 204.15.168.0/24 | 256 | ARIN | US | 9th Sept 2005 |
| 204.15.170.0/24 | 256 | ARIN | US | 23rd Aug 2011 |
| 204.15.180.0/22 | 1k | ARIN | US | 14th Sept 2005 |
| 204.15.184.0/21 | 2k | ARIN |  CA | 19th Sept 2005 |
| 204.15.212.0/22 | 1k | ARIN | US | 27th Jul 2020 |
| 204.15.216.0/22 | 1k | ARIN | US | 22nd Sept 2005 |
| 204.15.34.0/23 | 512 | ARIN | US | 17th Apr 2024 |
| 204.15.42.0/24 | 256 | ARIN | US | 21st Jul 2022 |
| 204.15.47.0/24 | 256 | ARIN | US | 8th Jul 2022 |
| 204.15.88.0/21 | 2k | ARIN | US | 17th Aug 2005 |
| 204.152.10.0/23 | 512 | ARIN | US | 23rd Sept 1994 |
| 204.152.106.0/23 | 512 | ARIN | US | 2nd Feb 1995 |
| 204.152.108.0/23 | 512 | ARIN | US | 2nd Feb 1995 |
| 204.152.118.0/23 | 512 | ARIN | US | 21st Feb 1995 |
| 204.152.120.0/23 | 512 | ARIN | US | 28th Feb 1995 |
| 204.152.122.0/23 | 512 | ARIN | US | 28th Feb 1995 |
| 204.152.124.0/23 | 512 | ARIN | US | 28th Feb 1995 |
| 204.152.126.0/23 | 512 | ARIN | US | 1st Mar 1995 |
| 204.152.136.0/23 | 512 | ARIN | US | 4th Mar 1995 |
| 204.152.138.0/23 | 512 | ARIN | US | 8th Mar 1995 |
| 204.152.14.0/23 | 512 | AFRINIC |  NA | 13th Oct 1994 |
| 204.152.142.0/23 | 512 | ARIN | US | 10th Mar 1995 |
| 204.152.144.0/23 | 512 | ARIN | US | 17th Mar 1995 |
| 204.152.146.0/23 | 512 | ARIN | US | 10th Feb 2011 |
| 204.152.16.0/23 | 512 | ARIN | US | 17th Oct 1994 |
| 204.152.160.0/22 | 1k | ARIN | US | 13th Feb 1996 |