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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,300 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 205.175.248.0/23 | 512 | ARIN |  US | 12th Nov 1996 |
| 205.175.251.0/24 | 256 | ARIN | US | 12th Nov 1996 |
| 205.175.252.0/22 | 1k | ARIN | US | 12th Nov 1996 |
| 205.175.32.0/19 | 8.2k | ARIN | US | 23rd Mar 1995 |
| 205.175.64.0/19 | 8.2k | ARIN | US | 3rd Apr 1995 |
| 205.178.150.0/23 | 512 | ARIN | US | 9th Apr 2021 |
| 205.178.171.0/24 | 256 | ARIN | US | 12th Apr 2021 |
| 205.178.172.0/22 | 1k | ARIN | US | 8th Mar 2021 |
| 205.184.0.0/19 | 8.2k | ARIN | US | 19th Jul 2000 |
| 205.184.32.0/20 | 4.1k | ARIN | US | 19th Jul 2000 |
| 205.185.224.0/20 | 4.1k | ARIN | US | 10th Aug 2009 |
| 205.187.128.0/19 | 8.2k | ARIN | US | 25th Nov 2024 |
| 205.187.176.0/20 | 4.1k | ARIN | US | 21st Mar 1995 |
| 205.187.192.0/18 | 16.4k | ARIN | US | 21st Mar 1995 |
| 205.189.0.0/24 | 256 | ARIN | US | 2nd Feb 2012 |
| 205.189.112.0/22 | 1k | ARIN | US | 22nd Mar 1995 |
| 205.189.238.0/23 | 512 | ARIN | US | 22nd Mar 1995 |
| 205.189.85.0/24 | 256 | ARIN | US | 22nd Mar 1995 |
| 205.190.0.0/16 | 65.5k | ARIN | US | 22nd Mar 1995 |
| 205.191.0.0/16 | 65.5k | ARIN | US | 9th Nov 2023 |
| 205.196.100.0/24 | 256 | ARIN | US | 1st Nov 1995 |
| 205.196.101.0/24 | 256 | ARIN | US | 1st Nov 1995 |
| 205.196.102.0/24 | 256 | ARIN | US | 1st Nov 1995 |
| 205.196.103.0/24 | 256 | ARIN | US | 1st Nov 1995 |
| 205.196.104.0/24 | 256 | ARIN | US | 1st Nov 1995 |
| 205.196.105.0/24 | 256 | ARIN | US | 14th Nov 1995 |
| 205.196.106.0/24 | 256 | ARIN | US | 1st Nov 1995 |
| 205.196.107.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.108.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.109.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.110.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.111.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.112.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.113.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.114.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.115.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.116.0/24 | 256 | ARIN | US | 14th Nov 1995 |
| 205.196.161.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.162.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.163.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.164.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.165.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.192.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.193.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.194.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.195.0/24 | 256 | ARIN | US | 14th Nov 1995 |
| 205.196.196.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.197.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.198.0/24 | 256 | ARIN | US | 17th Nov 1995 |
| 205.196.199.0/24 | 256 | ARIN | US | 17th Nov 1995 |