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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,356 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 206.41.160.0/19 | 8.2k | ARIN |  US | 16th Jun 1995 |
| 206.51.0.0/24 | 256 | ARIN |  PR | 14th Jan 2011 |
| 206.51.16.0/22 | 1k | ARIN |  CA | 16th Jan 1996 |
| 206.51.2.0/23 | 512 | ARIN | CA | 30th Nov 1995 |
| 206.51.20.0/23 | 512 | ARIN | CA | 16th Jan 1996 |
| 206.51.22.0/24 | 256 | ARIN | CA | 16th Jan 1996 |
| 206.51.27.0/24 | 256 | ARIN | CA | 18th Jan 1996 |
| 206.51.29.0/24 | 256 | ARIN | CA | 29th Feb 1996 |
| 206.51.30.0/24 | 256 | ARIN | US | 6th Sept 2007 |
| 206.51.31.0/24 | 256 | ARIN | CA | 19th Mar 1999 |
| 206.51.32.0/24 | 256 | ARIN | CA | 11th Mar 1996 |
| 206.51.34.0/24 | 256 | ARIN | CA | 14th Mar 1996 |
| 206.51.36.0/22 | 1k | ARIN | US | 8th Jun 2007 |
| 206.51.4.0/24 | 256 | ARIN | CA | 6th Dec 1995 |
| 206.51.40.0/21 | 2k | ARIN | US | 30th Jul 2007 |
| 206.51.5.0/24 | 256 | ARIN | CA | 20th Dec 1995 |
| 206.51.6.0/24 | 256 | ARIN | CA | 18th Dec 1995 |
| 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 |
| 206.53.138.0/24 | 256 | ARIN |  GB | 11th Feb 2015 |
| 206.53.139.0/24 | 256 | ARIN | US | 26th Feb 2015 |
| 206.53.140.0/24 | 256 | ARIN | CA | 31st Mar 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 |
| 206.53.203.0/24 | 256 | ARIN | US | 11th Apr 2016 |
| 206.53.204.0/24 | 256 | ARIN | US | 3rd Jun 2016 |
| 206.53.205.0/24 | 256 | ARIN | US | 22nd Aug 2016 |
| 206.53.206.0/24 | 256 | ARIN | US | 8th Sept 2016 |
| 206.53.207.0/24 | 256 | ARIN | US | 15th Nov 2016 |
| 206.53.32.0/21 | 2k | ARIN | US | 20th Jun 1995 |
| 206.53.40.0/21 | 2k | ARIN | US | 14th Nov 2008 |
| 206.54.224.0/19 | 8.2k | ARIN | US | 24th Jul 1995 |
| 206.55.160.0/22 | 1k | ARIN | US | 25th Jul 1995 |
| 206.55.164.0/22 | 1k | ARIN | US | 2nd Jul 2025 |
| 206.55.168.0/22 | 1k | ARIN | US | 17th Nov 2008 |
| 206.55.196.0/22 | 1k | ARIN | US | 13th Nov 2013 |
| 206.55.200.0/21 | 2k | ARIN | US | 18th Nov 2008 |
| 206.55.221.0/24 | 256 | ARIN | US | 17th Feb 2023 |
| 206.55.224.0/19 | 8.2k | ARIN | US | 9th Jul 2019 |
| 206.55.96.0/22 | 1k | ARIN | US | 24th Jul 1995 |
| 206.56.0.0/17 | 32.8k | ARIN | US | 22nd Jun 1995 |
| 206.60.0.0/16 | 65.5k | ARIN | US | 5th Jul 1995 |