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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 208.157.192.0/18 | 16.4k | ARIN |  US | 27th Mar 1996 |
| 208.162.0.0/16 | 65.5k | ARIN | US | 27th Mar 1996 |
| 208.164.0.0/15 | 131k | ARIN | US | 27th Mar 1996 |
| 208.166.128.0/17 | 32.8k | ARIN | US | 27th Mar 1996 |
| 208.166.32.0/20 | 4.1k | ARIN | US | 27th Mar 1996 |
| 208.168.128.0/18 | 16.4k | ARIN | US | 27th Mar 1996 |
| 208.39.0.0/17 | 32.8k | ARIN | US | 25th Jun 1999 |
| 208.52.136.0/24 | 256 | ARIN | US | 18th Nov 2020 |
| 208.52.143.0/24 | 256 | ARIN | US | 8th Dec 2016 |
| 208.52.169.0/24 | 256 | ARIN | US | 1st Jun 2020 |
| 208.52.184.0/24 | 256 | ARIN | US | 26th Jun 2024 |
| 208.52.192.0/18 | 16.4k | ARIN | US | 21st May 2002 |
| 208.64.100.0/22 | 1k | ARIN | US | 16th Dec 2005 |
| 208.64.120.0/21 | 2k | ARIN | US | 22nd Dec 2005 |
| 208.64.152.0/24 | 256 | ARIN | US | 24th Apr 2020 |
| 208.64.188.0/22 | 1k | ARIN | US | 4th Jan 2006 |
| 208.64.204.0/22 | 1k | ARIN | US | 18th Jan 2006 |
| 208.64.232.0/21 | 2k | ARIN | US | 18th Jan 2006 |
| 208.65.132.0/22 | 1k | ARIN | US | 27th Feb 2006 |
| 208.65.176.0/22 | 1k | ARIN | US | 6th Mar 2006 |
| 208.65.224.0/21 | 2k | ARIN | US | 14th Mar 2006 |
| 208.65.252.0/23 | 512 | ARIN | US | 5th Feb 2020 |
| 208.66.124.0/22 | 1k | ARIN | US | 20th Apr 2006 |
| 208.66.180.0/22 | 1k | ARIN | US | 26th Apr 2006 |
| 208.66.200.0/22 | 1k | ARIN | US | 28th Apr 2006 |
| 208.66.204.0/22 | 1k | ARIN | US | 1st May 2006 |
| 208.66.216.0/22 | 1k | ARIN | US | 3rd May 2006 |
| 208.66.64.0/22 | 1k | ARIN | US | 22nd Aug 2018 |
| 208.67.132.0/22 | 1k | ARIN | US | 21st Aug 2018 |
| 208.67.172.0/22 | 1k | ARIN | US | 1st Jun 2006 |
| 208.67.64.0/21 | 2k | ARIN | US | 15th May 2006 |
| 208.67.72.0/22 | 1k | ARIN | US | 1st Jul 2026 |
| 208.67.76.0/22 | 1k | ARIN | US | 17th May 2006 |
| 208.68.176.0/22 | 1k | ARIN | US | 6th Jul 2006 |
| 208.68.212.0/22 | 1k | ARIN | US | 11th Jul 2006 |
| 208.68.228.0/22 | 1k | ARIN | US | 18th Jul 2006 |
| 208.68.52.0/22 | 1k | ARIN | US | 16th Jun 2006 |
| 208.69.104.0/22 | 1k | ARIN | US | 8th Aug 2006 |
| 208.69.152.0/21 | 2k | ARIN | US | 15th Aug 2006 |
| 208.69.176.0/21 | 2k | ARIN | US | 30th Mar 2021 |
| 208.69.192.0/23 | 512 | ARIN | US | 31st Jan 2017 |
| 208.69.20.0/22 | 1k | ARIN | US | 26th Jul 2006 |
| 208.69.44.0/22 | 1k | ARIN | US | 31st Jul 2006 |
| 208.70.124.0/22 | 1k | ARIN | US | 28th Jul 2026 |
| 208.70.168.0/24 | 256 | ARIN | US | 17th Apr 2017 |
| 208.70.188.0/22 | 1k | ARIN | US | 25th Sept 2006 |
| 208.70.192.0/22 | 1k | ARIN | US | 26th Sept 2006 |
| 208.70.224.0/22 | 1k | ARIN | US | 28th Sept 2006 |
| 208.70.228.0/22 | 1k | ARIN | US | 29th Sept 2006 |
| 208.70.232.0/21 | 2k | ARIN | US | 2nd Oct 2006 |