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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks registered through ARIN
30,479 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 205.237.21.0/24 | 256 | ARIN |  CA | 18th Oct 1995 |
| 205.237.225.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.237.236.0/24 | 256 | ARIN | CA | 17th May 1996 |
| 205.237.237.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.237.240.0/23 | 512 | ARIN | CA | 25th Apr 1995 |
| 205.237.248.0/22 | 1k | ARIN | CA | 25th Apr 1995 |
| 205.237.254.0/24 | 256 | ARIN | CA | 25th Sept 1995 |
| 205.237.255.0/24 | 256 | ARIN |  US | 18th Dec 2018 |
| 205.237.26.0/24 | 256 | ARIN | CA | 3rd Nov 1995 |
| 205.237.28.0/24 | 256 | ARIN | CA | 5th Apr 1996 |
| 205.237.3.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.237.4.0/23 | 512 | ARIN | CA | 25th Apr 1995 |
| 205.237.6.0/23 | 512 | ARIN | CA | 25th Apr 1995 |
| 205.249.0.0/16 | 65.5k | ARIN | US | 28th Apr 1995 |
| 205.251.146.0/23 | 512 | ARIN | US | 24th Apr 2018 |
| 205.254.32.0/19 | 8.2k | ARIN | US | 9th May 1995 |
| 205.254.64.0/18 | 16.4k | ARIN | US | 9th May 1995 |
| 206.108.1.0/24 | 256 | ARIN | CA | 30th Aug 1995 |
| 206.108.112.0/24 | 256 | ARIN | CA | 16th Jan 1996 |
| 206.108.114.0/24 | 256 | ARIN | US | 4th Mar 2014 |
| 206.108.115.0/24 | 256 | ARIN |  NL | 12th Mar 2014 |
| 206.108.12.0/22 | 1k | ARIN | CA | 25th Sept 1995 |
| 206.108.2.0/24 | 256 | ARIN | CA | 30th Aug 1995 |
| 206.108.236.0/24 | 256 | ARIN | US | 1st Feb 2012 |
| 206.108.237.0/24 | 256 | ARIN | CA | 28th Nov 1995 |
| 206.108.238.0/24 | 256 | ARIN | CA | 9th Nov 1995 |
| 206.108.240.0/23 | 512 | ARIN | CA | 19th Oct 1995 |
| 206.108.242.0/24 | 256 | ARIN | CA | 2nd Nov 1995 |
| 206.108.243.0/24 | 256 | ARIN | CA | 20th Oct 1995 |
| 206.108.244.0/23 | 512 | ARIN | CA | 3rd Oct 1995 |
| 206.108.246.0/24 | 256 | ARIN | CA | 3rd Oct 1995 |
| 206.108.247.0/24 | 256 | ARIN | CA | 23rd Oct 1995 |
| 206.108.248.0/24 | 256 | ARIN | CA | 16th Oct 1995 |
| 206.108.249.0/24 | 256 | ARIN | CA | 3rd Oct 1995 |
| 206.108.255.0/24 | 256 | ARIN | US | 6th Aug 2012 |
| 206.108.3.0/24 | 256 | ARIN | CA | 30th Aug 1995 |
| 206.108.32.0/24 | 256 | ARIN | US | 27th Oct 1995 |
| 206.108.33.0/24 | 256 | ARIN | CA | 27th Oct 1995 |
| 206.108.36.0/22 | 1k | ARIN | CA | 1st Nov 1995 |
| 206.108.56.0/24 | 256 | ARIN | CA | 21st Dec 1995 |
| 206.108.57.0/24 | 256 | ARIN | CA | 4th Dec 1995 |
| 206.108.59.0/24 | 256 | ARIN | CA | 6th Dec 1995 |
| 206.108.61.0/24 | 256 | ARIN | CA | 4th Dec 1995 |
| 206.108.62.0/24 | 256 | ARIN | CA | 28th Nov 1995 |
| 206.108.8.0/23 | 512 | ARIN | CA | 21st Sept 1995 |
| 206.109.0.0/20 | 4.1k | ARIN | US | 17th Aug 1995 |
| 206.109.106.0/23 | 512 | ARIN | US | 4th Feb 2026 |
| 206.109.110.0/23 | 512 | ARIN | US | 17th Aug 1995 |
| 206.109.116.0/22 | 1k | ARIN | US | 5th Jun 2026 |
| 206.109.128.0/19 | 8.2k | ARIN | US | 16th Oct 2025 |