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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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.
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Countries with unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,295 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 206.223.99.0/24 | 256 | ARIN |  US | 9th Jul 1996 |
| 206.224.128.0/19 | 8.2k | ARIN | US | 23rd Oct 1995 |
| 206.224.160.0/19 | 8.2k | ARIN | US | 25th Oct 1995 |
| 206.225.12.0/24 | 256 | ARIN | US | 24th Jan 2023 |
| 206.225.133.0/24 | 256 | ARIN | US | 15th Jul 2015 |
| 206.225.14.0/24 | 256 | ARIN | US | 13th May 2022 |
| 206.225.15.0/24 | 256 | ARIN | US | 24th Jan 2023 |
| 206.225.16.0/24 | 256 | ARIN | US | 4th Oct 2022 |
| 206.225.160.0/22 | 1k | ARIN | US | 27th Nov 1995 |
| 206.225.5.0/24 | 256 | ARIN | US | 24th Jan 2023 |
| 206.225.6.0/23 | 512 | ARIN | US | 24th Jan 2023 |
| 206.225.64.0/22 | 1k | ARIN | US | 7th Nov 1995 |
| 206.225.9.0/24 | 256 | ARIN | US | 20th Sept 2022 |
| 206.226.0.0/18 | 16.4k | ARIN | US | 6th Oct 1995 |
| 206.245.0.0/18 | 16.4k | ARIN | US | 27th Nov 1995 |
| 206.245.64.0/18 | 16.4k | ARIN | US | 20th Dec 1995 |
| 206.246.32.0/19 | 8.2k | ARIN | US | 10th Apr 1996 |
| 206.251.128.0/19 | 8.2k | ARIN | US | 25th Jan 1996 |
| 206.251.56.0/22 | 1k | ARIN | US | 6th Oct 2025 |
| 206.251.96.0/19 | 8.2k | ARIN | US | 23rd Jan 1996 |
| 206.252.0.0/19 | 8.2k | ARIN | US | 12th Dec 2000 |
| 206.253.96.0/19 | 8.2k | ARIN | US | 24th Jun 1996 |
| 206.28.184.0/21 | 2k | ARIN | US | 24th May 1995 |
| 206.29.0.0/17 | 32.8k | ARIN | US | 24th May 1995 |
| 206.29.144.0/20 | 4.1k | ARIN | US | 24th May 1995 |
| 206.29.192.0/18 | 16.4k | ARIN | US | 24th May 1995 |
| 206.40.0.0/19 | 8.2k | ARIN | US | 30th May 1995 |
| 206.40.64.0/19 | 8.2k | ARIN | US | 2nd Jun 1995 |
| 206.41.105.0/24 | 256 | ARIN | US | 20th May 2014 |
| 206.41.108.0/24 | 256 | ARIN | US | 17th Sept 2014 |
| 206.41.109.0/24 | 256 | ARIN | US | 18th Sept 2014 |
| 206.41.110.0/24 | 256 | ARIN | US | 17th Oct 2014 |
| 206.41.128.0/20 | 4.1k | ARIN | US | 16th Jun 1995 |
| 206.41.160.0/19 | 8.2k | ARIN | US | 16th Jun 1995 |
| 206.51.30.0/24 | 256 | ARIN | US | 6th Sept 2007 |
| 206.51.36.0/22 | 1k | ARIN | US | 8th Jun 2007 |
| 206.51.40.0/21 | 2k | ARIN | US | 30th Jul 2007 |
| 206.51.7.0/24 | 256 | ARIN | US | 6th Jul 2007 |
| 206.53.128.0/21 | 2k | ARIN | US | 21st Jun 1995 |
| 206.53.137.0/24 | 256 | ARIN | US | 8th Jan 2015 |
| 206.53.139.0/24 | 256 | ARIN | US | 26th Feb 2015 |
| 206.53.143.0/24 | 256 | ARIN | US | 15th Apr 2015 |
| 206.53.16.0/20 | 4.1k | ARIN | US | 4th Aug 2004 |
| 206.53.168.0/22 | 1k | ARIN | US | 19th Oct 2015 |
| 206.53.172.0/23 | 512 | ARIN | US | 19th Oct 2015 |
| 206.53.174.0/24 | 256 | ARIN | US | 19th Oct 2015 |
| 206.53.175.0/24 | 256 | ARIN | US | 4th Nov 2015 |
| 206.53.200.0/24 | 256 | ARIN | US | 2nd Dec 2015 |
| 206.53.201.0/24 | 256 | ARIN | US | 22nd Feb 2016 |
| 206.53.202.0/24 | 256 | ARIN | US | 14th Mar 2016 |