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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,315 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 199.74.150.0/24 | 256 | ARIN |  US | 22nd Jan 1994 |
| 199.74.151.0/24 | 256 | ARIN | US | 22nd Jan 1994 |
| 199.74.152.0/24 | 256 | ARIN | US | 22nd Jan 1994 |
| 199.74.158.0/24 | 256 | ARIN | US | 22nd Jan 1994 |
| 199.74.16.0/20 | 4.1k | ARIN | US | 3rd Dec 1993 |
| 199.74.160.0/23 | 512 | ARIN | US | 9th Jul 2012 |
| 199.74.163.0/24 | 256 | ARIN | US | 24th Jan 1994 |
| 199.74.164.0/23 | 512 | ARIN | US | 24th Jan 1994 |
| 199.74.166.0/24 | 256 | ARIN | US | 24th Jan 1994 |
| 199.74.167.0/24 | 256 | ARIN | US | 24th Jan 1994 |
| 199.74.168.0/24 | 256 | ARIN | US | 24th Jan 1994 |
| 199.74.169.0/24 | 256 | ARIN | US | 24th Jan 1994 |
| 199.74.170.0/24 | 256 | ARIN | US | 24th Jan 1994 |
| 199.74.171.0/24 | 256 | ARIN | US | 24th Jan 1994 |
| 199.74.176.0/24 | 256 | ARIN | US | 24th Jan 1994 |
| 199.74.177.0/24 | 256 | ARIN | US | 24th Jan 1994 |
| 199.74.178.0/23 | 512 | ARIN | US | 24th Jan 1994 |
| 199.74.180.0/23 | 512 | ARIN | US | 24th Jan 1994 |
| 199.74.186.0/24 | 256 | ARIN | US | 25th Jan 1994 |
| 199.74.193.0/24 | 256 | ARIN | US | 25th Jan 1994 |
| 199.74.194.0/23 | 512 | ARIN | US | 25th Jan 1994 |
| 199.74.196.0/24 | 256 | ARIN | US | 25th Jan 1994 |
| 199.74.197.0/24 | 256 | ARIN | US | 25th Jan 1994 |
| 199.74.198.0/24 | 256 | ARIN | US | 25th Jan 1994 |
| 199.74.199.0/24 | 256 | ARIN | US | 25th Jan 1994 |
| 199.74.200.0/24 | 256 | ARIN | US | 26th Jan 1994 |
| 199.74.201.0/24 | 256 | ARIN | US | 26th Jan 1994 |
| 199.74.202.0/24 | 256 | ARIN | US | 26th Jan 1994 |
| 199.74.203.0/24 | 256 | ARIN | US | 26th Jan 1994 |
| 199.74.204.0/24 | 256 | ARIN | US | 26th Jan 1994 |
| 199.74.206.0/24 | 256 | ARIN | US | 26th Jan 1994 |
| 199.74.207.0/24 | 256 | ARIN | US | 26th Jan 1994 |
| 199.74.208.0/24 | 256 | ARIN | US | 26th Jan 1994 |
| 199.74.209.0/24 | 256 | ARIN | US | 26th Jan 1994 |
| 199.74.210.0/24 | 256 | ARIN | US | 22nd Jun 2011 |
| 199.74.211.0/24 | 256 | ARIN | US | 26th Jan 1994 |
| 199.74.212.0/24 | 256 | ARIN | US | 26th Jan 1994 |
| 199.74.214.0/24 | 256 | ARIN | US | 26th Jan 1994 |
| 199.74.215.0/24 | 256 | ARIN | US | 26th Jan 1994 |
| 199.74.223.0/24 | 256 | ARIN | US | 27th Jan 1994 |
| 199.74.224.0/22 | 1k | ARIN | US | 27th Jan 1994 |
| 199.74.229.0/24 | 256 | ARIN | US | 28th Jan 1994 |
| 199.74.232.0/24 | 256 | ARIN | US | 28th Jan 1994 |
| 199.74.233.0/24 | 256 | ARIN | US | 28th Jan 1994 |
| 199.74.234.0/24 | 256 | ARIN | US | 28th Jan 1994 |
| 199.74.235.0/24 | 256 | ARIN | US | 2nd Jul 2025 |
| 199.74.238.0/23 | 512 | ARIN | US | 28th Jan 1994 |
| 199.74.240.0/23 | 512 | ARIN | US | 28th Jan 1994 |
| 199.74.242.0/24 | 256 | ARIN | US | 31st Jan 1994 |
| 199.74.243.0/24 | 256 | ARIN | US | 31st Jan 1994 |