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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,315 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 198.187.221.0/24 | 256 | ARIN |  US | 30th Sept 1993 |
| 198.187.224.0/24 | 256 | ARIN | US | 1st Oct 1993 |
| 198.187.225.0/24 | 256 | ARIN | US | 1st Oct 1993 |
| 198.187.226.0/24 | 256 | ARIN | US | 1st Oct 1993 |
| 198.187.227.0/24 | 256 | ARIN | US | 4th Oct 1993 |
| 198.187.228.0/24 | 256 | ARIN | US | 4th Oct 1993 |
| 198.187.229.0/24 | 256 | ARIN | US | 4th Oct 1993 |
| 198.187.230.0/24 | 256 | ARIN | US | 4th Oct 1993 |
| 198.187.231.0/24 | 256 | ARIN | US | 4th Oct 1993 |
| 198.187.237.0/24 | 256 | ARIN | US | 4th Oct 1993 |
| 198.187.238.0/24 | 256 | ARIN | US | 4th Oct 1993 |
| 198.187.239.0/24 | 256 | ARIN | US | 7th Apr 2025 |
| 198.187.24.0/22 | 1k | ARIN | US | 22nd Jun 1993 |
| 198.187.240.0/24 | 256 | ARIN | US | 4th Oct 1993 |
| 198.187.241.0/24 | 256 | ARIN | US | 4th Oct 1993 |
| 198.187.242.0/23 | 512 | ARIN | US | 4th Oct 1993 |
| 198.187.244.0/23 | 512 | ARIN | US | 4th Oct 1993 |
| 198.187.246.0/24 | 256 | ARIN | US | 4th Oct 1993 |
| 198.187.250.0/24 | 256 | ARIN | US | 5th Oct 1993 |
| 198.187.252.0/24 | 256 | ARIN | US | 5th Oct 1993 |
| 198.187.254.0/24 | 256 | ARIN | US | 6th Oct 1993 |
| 198.187.255.0/24 | 256 | ARIN | US | 29th Jan 2013 |
| 198.187.64.0/18 | 16.4k | ARIN | US | 17th Sept 1993 |
| 198.190.12.0/24 | 256 | ARIN | US | 13th Dec 1993 |
| 198.190.132.0/24 | 256 | ARIN | US | 31st Jan 2013 |
| 198.190.138.0/24 | 256 | ARIN | US | 24th Jul 2019 |
| 198.190.139.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.140.0/22 | 1k | ARIN | US | 2nd Feb 1994 |
| 198.190.144.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.145.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.146.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.147.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.148.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.152.0/22 | 1k | ARIN | US | 2nd Feb 1994 |
| 198.190.158.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.159.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.161.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.162.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.163.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.165.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.168.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.170.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.172.0/24 | 256 | ARIN | US | 2nd Feb 1994 |
| 198.190.173.0/24 | 256 | ARIN | US | 3rd Feb 1994 |
| 198.190.174.0/24 | 256 | ARIN | US | 3rd Feb 1994 |
| 198.190.175.0/24 | 256 | ARIN | US | 3rd Feb 1994 |
| 198.190.176.0/24 | 256 | ARIN | US | 3rd Feb 1994 |
| 198.190.177.0/24 | 256 | ARIN | US | 3rd Feb 1994 |
| 198.190.178.0/24 | 256 | ARIN | US | 3rd Feb 1994 |
| 198.190.180.0/24 | 256 | ARIN | US | 3rd Feb 1994 |