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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,302 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 198.151.142.0/24 | 256 | ARIN |  US | 18th Jun 1993 |
| 198.151.144.0/24 | 256 | ARIN | US | 6th Nov 2013 |
| 198.151.145.0/24 | 256 | ARIN | US | 18th Jun 1993 |
| 198.151.146.0/24 | 256 | ARIN | US | 18th Jun 1993 |
| 198.151.147.0/24 | 256 | ARIN | US | 18th Jun 1993 |
| 198.151.148.0/24 | 256 | ARIN | US | 18th Jun 1993 |
| 198.151.149.0/24 | 256 | ARIN | US | 18th Jun 1993 |
| 198.151.150.0/24 | 256 | ARIN | US | 18th Jun 1993 |
| 198.151.151.0/24 | 256 | ARIN | US | 18th Jun 1993 |
| 198.151.152.0/22 | 1k | ARIN | US | 21st Jun 1993 |
| 198.151.156.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.158.0/24 | 256 | ARIN | US | 6th Nov 2013 |
| 198.151.159.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.16.0/20 | 4.1k | ARIN | US | 10th May 1993 |
| 198.151.160.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.161.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.162.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.163.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.164.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.165.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.167.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.168.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.169.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.170.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.171.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.172.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.173.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.174.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.176.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.177.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.151.184.0/24 | 256 | ARIN | US | 22nd Jun 1993 |
| 198.151.185.0/24 | 256 | ARIN | US | 22nd Jun 1993 |
| 198.151.186.0/24 | 256 | ARIN | US | 22nd Jun 1993 |
| 198.151.188.0/24 | 256 | ARIN | US | 22nd Jun 1993 |
| 198.151.189.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.151.190.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.151.191.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.151.192.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.151.193.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.151.194.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.151.195.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.151.196.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.151.197.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.151.198.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.151.204.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.151.205.0/24 | 256 | ARIN | US | 18th Mar 2022 |
| 198.151.206.0/24 | 256 | ARIN | US | 8th Nov 2013 |
| 198.151.207.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.151.209.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.151.210.0/24 | 256 | ARIN | US | 23rd Jun 1993 |