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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 in United States
27,019 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 205.210.125.0/24 | 256 | ARIN |  US | 29th Dec 2011 |
| 205.210.142.0/24 | 256 | ARIN | US | 8th Apr 1995 |
| 205.210.145.0/24 | 256 | ARIN | US | 5th Jan 2012 |
| 205.210.149.0/24 | 256 | ARIN | US | 22nd Dec 2011 |
| 205.210.186.0/23 | 512 | ARIN | US | 16th Mar 2012 |
| 205.210.232.0/23 | 512 | ARIN | US | 8th Apr 1995 |
| 205.210.245.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 205.210.248.0/24 | 256 | ARIN | US | 10th Jan 2012 |
| 205.210.255.0/24 | 256 | ARIN | US | 23rd Jan 2012 |
| 205.210.36.0/24 | 256 | ARIN | US | 8th Apr 1995 |
| 205.210.70.0/24 | 256 | ARIN | US | 1st Jul 2025 |
| 205.214.128.0/19 | 8.2k | ARIN | US | 18th Apr 1995 |
| 205.214.96.0/19 | 8.2k | ARIN | US | 18th Apr 1995 |
| 205.220.218.0/24 | 256 | ARIN | US | 20th Jul 2018 |
| 205.220.220.0/22 | 1k | ARIN | US | 25th Sept 2018 |
| 205.223.128.0/20 | 4.1k | ARIN | US | 31st May 1995 |
| 205.223.32.0/20 | 4.1k | ARIN | US | 22nd Jun 2026 |
| 205.223.48.0/20 | 4.1k | ARIN | US | 28th Apr 1995 |
| 205.223.64.0/20 | 4.1k | ARIN | US | 2nd May 1995 |
| 205.223.80.0/20 | 4.1k | ARIN | US | 5th May 1995 |
| 205.233.126.0/23 | 512 | ARIN | US | 26th Apr 2024 |
| 205.233.147.0/24 | 256 | ARIN | US | 26th Sept 1996 |
| 205.233.24.0/21 | 2k | ARIN | US | 31st Jul 2025 |
| 205.233.255.0/24 | 256 | ARIN | US | 21st Nov 2011 |
| 205.233.39.0/24 | 256 | ARIN | US | 16th Nov 2011 |
| 205.233.74.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 205.233.75.0/24 | 256 | ARIN | US | 13th Jan 2021 |
| 205.235.144.0/20 | 4.1k | ARIN | US | 14th Jun 1995 |
| 205.235.176.0/20 | 4.1k | ARIN | US | 20th Jun 1995 |
| 205.235.240.0/20 | 4.1k | ARIN | US | 13th Jul 1995 |
| 205.235.64.0/20 | 4.1k | ARIN | US | 8th Jun 1995 |
| 205.236.255.0/24 | 256 | ARIN | US | 2nd Dec 2011 |
| 205.236.51.0/24 | 256 | ARIN | US | 26th Sept 1996 |
| 205.236.75.0/24 | 256 | ARIN | US | 26th Sept 1996 |
| 205.237.255.0/24 | 256 | ARIN | US | 18th Dec 2018 |
| 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 |
| 206.108.114.0/24 | 256 | ARIN | US | 4th Mar 2014 |
| 206.108.236.0/24 | 256 | ARIN | US | 1st Feb 2012 |
| 206.108.255.0/24 | 256 | ARIN | US | 6th Aug 2012 |
| 206.108.32.0/24 | 256 | ARIN | US | 27th Oct 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 |
| 206.109.16.0/21 | 2k | ARIN | US | 17th Aug 1995 |
| 206.109.160.0/19 | 8.2k | ARIN | US | 17th Aug 1995 |