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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 the most unannounced blocks, largest first.
Unannounced blocks in United States
26,951 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 205.196.74.0/24 | 256 | ARIN |  US | 25th Aug 1995 |
| 205.196.75.0/24 | 256 | ARIN | US | 1st Nov 1995 |
| 205.196.76.0/24 | 256 | ARIN | US | 1st Nov 1995 |
| 205.196.96.0/24 | 256 | ARIN | US | 1st Nov 1995 |
| 205.196.97.0/24 | 256 | ARIN | US | 1st Nov 1995 |
| 205.196.98.0/24 | 256 | ARIN | US | 7th Dec 2011 |
| 205.196.99.0/24 | 256 | ARIN | US | 25th Oct 1995 |
| 205.203.0.0/19 | 8.2k | ARIN | US | 7th Apr 1995 |
| 205.203.208.0/21 | 2k | ARIN | US | 26th May 1995 |
| 205.203.224.0/19 | 8.2k | ARIN | US | 8th Jun 1995 |
| 205.207.156.0/22 | 1k | ARIN | US | 2nd Dec 2008 |
| 205.207.170.0/23 | 512 | ARIN | US | 22nd Sept 1995 |
| 205.207.212.0/23 | 512 | ARIN | US | 5th Oct 2026 |
| 205.207.246.0/23 | 512 | ARIN | US | 8th Apr 1995 |
| 205.207.254.0/24 | 256 | ARIN | US | 7th Oct 2026 |
| 205.207.74.0/24 | 256 | ARIN | US | 8th Apr 1995 |
| 205.208.128.0/18 | 16.4k | ARIN | US | 10th Nov 2026 |
| 205.209.0.0/24 | 256 | ARIN | US | 27th Dec 2011 |
| 205.209.24.0/24 | 256 | ARIN | US | 18th Mar 2026 |
| 205.209.27.0/24 | 256 | ARIN | US | 1st Jun 2026 |
| 205.209.28.0/24 | 256 | RIPE NCC | US | 2nd Mar 2017 |
| 205.209.7.0/24 | 256 | ARIN | US | 29th Dec 2011 |
| 205.210.0.0/24 | 256 | ARIN | US | 3rd Apr 2025 |
| 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 |
| 205.211.12.0/23 | 512 | ARIN | US | 6th Oct 2026 |
| 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 |