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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
27,001 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 2604:4440::/32 | 4.3B × /64 | ARIN |  US | 2nd Jun 2017 |
| 2604:46c0::/32 | 4.3B × /64 | ARIN | US | 12th Jan 2026 |
| 2604:4740::/32 | 4.3B × /64 | ARIN | US | 7th Jun 2017 |
| 2604:47c0::/32 | 4.3B × /64 | ARIN | US | 8th Jun 2017 |
| 2604:4800::/32 | 4.3B × /64 | ARIN | US | 16th Apr 2010 |
| 2604:4900::/32 | 4.3B × /64 | ARIN | US | 5th Apr 2011 |
| 2604:4980::/32 | 4.3B × /64 | ARIN | US | 17th Dec 2012 |
| 2604:4ac0::/32 | 4.3B × /64 | ARIN | US | 16th Jun 2017 |
| 2604:4b00::/32 | 4.3B × /64 | ARIN | US | 6th Apr 2011 |
| 2604:4b80::/32 | 4.3B × /64 | ARIN | US | 18th Dec 2012 |
| 2604:4c0::/32 | 4.3B × /64 | ARIN | US | 29th Dec 2016 |
| 2604:4c80::/32 | 4.3B × /64 | ARIN | US | 20th Dec 2012 |
| 2604:4d00::/32 | 4.3B × /64 | ARIN | US | 6th Apr 2011 |
| 2604:4e00::/32 | 4.3B × /64 | ARIN | US | 28th Oct 2010 |
| 2604:4e40::/32 | 4.3B × /64 | ARIN | US | 26th Jun 2017 |
| 2604:4fc0::/32 | 4.3B × /64 | ARIN | US | 3rd Jul 2017 |
| 2604:5040::/32 | 4.3B × /64 | ARIN | US | 3rd Jul 2017 |
| 2604:5080::/32 | 4.3B × /64 | ARIN | US | 28th Dec 2012 |
| 2604:50c0::/32 | 4.3B × /64 | ARIN | US | 3rd Jul 2017 |
| 2604:5100::/32 | 4.3B × /64 | ARIN | US | 7th Apr 2011 |
| 2604:5180::/32 | 4.3B × /64 | ARIN | US | 19th Aug 2026 |
| 2604:52c0::/32 | 4.3B × /64 | ARIN | US | 6th Jul 2017 |
| 2604:5300::/32 | 4.3B × /64 | ARIN | US | 7th Apr 2011 |
| 2604:53c0::/32 | 4.3B × /64 | ARIN | US | 7th Jul 2017 |
| 2604:5440::/32 | 4.3B × /64 | ARIN | US | 7th Jul 2017 |
| 2604:54c0::/32 | 4.3B × /64 | ARIN | US | 10th Jul 2017 |
| 2604:560::/32 | 4.3B × /64 | ARIN | US | 25th Feb 2025 |
| 2604:5740::/32 | 4.3B × /64 | ARIN | US | 18th Jul 2017 |
| 2604:58c0::/32 | 4.3B × /64 | ARIN | US | 19th Jul 2017 |
| 2604:5900::/32 | 4.3B × /64 | ARIN | US | 13th Jan 2026 |
| 2604:59c0::/32 | 4.3B × /64 | ARIN | US | 20th Jul 2017 |
| 2604:5a80::/32 | 4.3B × /64 | ARIN | US | 14th Jan 2013 |
| 2604:5ac0::/32 | 4.3B × /64 | ARIN | US | 28th Jul 2017 |
| 2604:5b40::/32 | 4.3B × /64 | ARIN | US | 31st Jul 2017 |
| 2604:5bc0::/32 | 4.3B × /64 | ARIN | US | 31st Jul 2017 |
| 2604:5c0::/32 | 4.3B × /64 | ARIN | US | 3rd Jan 2017 |
| 2604:5d40::/32 | 4.3B × /64 | ARIN | US | 3rd Aug 2017 |
| 2604:5dc0::/32 | 4.3B × /64 | ARIN | US | 4th Aug 2017 |
| 2604:5e00::/32 | 4.3B × /64 | ARIN | US | 3rd Nov 2010 |
| 2604:5e0::/32 | 4.3B × /64 | ARIN | US | 28th Feb 2025 |
| 2604:5f40::/32 | 4.3B × /64 | ARIN | US | 11th Aug 2017 |
| 2604:5fc0::/32 | 4.3B × /64 | ARIN | US | 14th Aug 2017 |
| 2604:600::/32 | 4.3B × /64 | ARIN | US | 19th Oct 2010 |
| 2604:6100::/32 | 4.3B × /64 | ARIN | US | 11th Apr 2011 |
| 2604:6180::/32 | 4.3B × /64 | ARIN | US | 25th Jan 2013 |
| 2604:6200::/32 | 4.3B × /64 | ARIN | US | 4th Nov 2010 |
| 2604:620::/32 | 4.3B × /64 | ARIN | US | 28th Feb 2025 |
| 2604:6240::/32 | 4.3B × /64 | ARIN | US | 21st Aug 2017 |
| 2604:62c0::/32 | 4.3B × /64 | ARIN | US | 21st Aug 2017 |
| 2604:6380::/32 | 4.3B × /64 | ARIN | US | 30th Jan 2013 |