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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,279 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 2604:360::/32 | 4.3B × /64 | ARIN |  US | 12th Feb 2025 |
| 2604:3640::/32 | 4.3B × /64 | ARIN | US | 20th Apr 2017 |
| 2604:3680::/32 | 4.3B × /64 | ARIN | US | 9th Nov 2012 |
| 2604:3780::/32 | 4.3B × /64 | ARIN | US | 14th Nov 2012 |
| 2604:37c0::/32 | 4.3B × /64 | ARIN | US | 24th Apr 2017 |
| 2604:3800::/32 | 4.3B × /64 | ARIN | US | 16th Apr 2010 |
| 2604:380::/32 | 4.3B × /64 | ARIN | US | 8th Aug 2012 |
| 2604:3880::/32 | 4.3B × /64 | ARIN | US | 3rd Dec 2012 |
| 2604:3980::/32 | 4.3B × /64 | ARIN | US | 13th Aug 2026 |
| 2604:39c0::/32 | 4.3B × /64 | ARIN | US | 27th Apr 2017 |
| 2604:3a40::/32 | 4.3B × /64 | ARIN | US | 19th Aug 2026 |
| 2604:3ac0::/32 | 4.3B × /64 | ARIN | US | 1st May 2017 |
| 2604:3b00::/32 | 4.3B × /64 | ARIN |  CA | 4th Apr 2011 |
| 2604:3bc0::/32 | 4.3B × /64 | ARIN | US | 2nd May 2017 |
| 2604:3c00::/32 | 4.3B × /64 | ARIN | US | 18th Jun 2010 |
| 2604:3c0::/32 | 4.3B × /64 | ARIN | US | 27th Dec 2016 |
| 2604:3c40::/32 | 4.3B × /64 | ARIN | US | 4th May 2017 |
| 2604:3e40::/32 | 4.3B × /64 | ARIN | CA | 9th May 2017 |
| 2604:3e80::/32 | 4.3B × /64 | ARIN | US | 10th Dec 2012 |
| 2604:3ec0::/32 | 4.3B × /64 | ARIN | US | 19th Aug 2026 |
| 2604:3f80::/32 | 4.3B × /64 | ARIN | US | 10th Dec 2012 |
| 2604:400::/32 | 4.3B × /64 | ARIN | CA | 16th Jun 2010 |
| 2604:4040::/32 | 4.3B × /64 | ARIN | US | 16th May 2017 |
| 2604:4140::/32 | 4.3B × /64 | ARIN | CA | 19th May 2017 |
| 2604:41c0::/32 | 4.3B × /64 | ARIN | US | 23rd May 2017 |
| 2604:4240::/36 | 268M × /64 | ARIN | CA | 25th May 2017 |
| 2604:4340::/32 | 4.3B × /64 | ARIN | US | 31st May 2017 |
| 2604:4380::/32 | 4.3B × /64 | ARIN | US | 8th Jan 2026 |
| 2604:43c0::/32 | 4.3B × /64 | ARIN | US | 1st Jun 2017 |
| 2604:4400::/32 | 4.3B × /64 | ARIN | US | 18th Jun 2010 |
| 2604:4440::/32 | 4.3B × /64 | ARIN | US | 2nd Jun 2017 |
| 2604:45c0::/32 | 4.3B × /64 | ARIN | CA | 7th Jun 2017 |
| 2604:4680::/32 | 4.3B × /64 | ARIN | CA | 14th Dec 2012 |
| 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 |
| 2604:48c0::/32 | 4.3B × /64 | ARIN | CA | 9th Jun 2017 |
| 2604:4900::/32 | 4.3B × /64 | ARIN | US | 5th Apr 2011 |
| 2604:4980::/32 | 4.3B × /64 | ARIN | US | 17th Dec 2012 |
| 2604:4a0::/32 | 4.3B × /64 | ARIN | CA | 24th Feb 2025 |
| 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 |