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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 198.136.227.0/24 | 256 | ARIN |  US | 15th Jun 1993 |
| 198.136.228.0/24 | 256 | ARIN | US | 15th Jun 1993 |
| 198.136.230.0/24 | 256 | ARIN | US | 15th Jun 1993 |
| 198.136.231.0/24 | 256 | ARIN | US | 15th Jun 1993 |
| 198.136.235.0/24 | 256 | ARIN | US | 18th Jun 1993 |
| 198.136.236.0/24 | 256 | ARIN | US | 18th Jun 1993 |
| 198.136.237.0/24 | 256 | ARIN | US | 18th Jun 1993 |
| 198.136.238.0/24 | 256 | ARIN | US | 7th Jun 2013 |
| 198.136.239.0/24 | 256 | ARIN | US | 18th Jun 1993 |
| 198.136.240.0/24 | 256 | ARIN | US | 18th Jun 1993 |
| 198.136.241.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.136.242.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.136.243.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.136.244.0/24 | 256 | ARIN | US | 21st Jun 1993 |
| 198.136.245.0/24 | 256 | ARIN | US | 22nd Jun 1993 |
| 198.136.246.0/24 | 256 | ARIN | US | 22nd Jun 1993 |
| 198.136.247.0/24 | 256 | ARIN | US | 22nd Jun 1993 |
| 198.136.248.0/24 | 256 | ARIN | US | 22nd Jun 1993 |
| 198.136.249.0/24 | 256 | ARIN | US | 22nd Jun 1993 |
| 198.136.251.0/24 | 256 | ARIN | US | 22nd Jun 1993 |
| 198.136.252.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.136.253.0/24 | 256 | ARIN | US | 23rd Jun 1993 |
| 198.136.254.0/24 | 256 | ARIN | US | 25th Jun 1993 |
| 198.137.0.0/21 | 2k | ARIN | US | 15th Apr 1993 |
| 198.137.128.0/24 | 256 | ARIN | US | 6th May 1993 |
| 198.137.129.0/24 | 256 | ARIN | US | 6th May 1993 |
| 198.137.130.0/24 | 256 | ARIN | US | 6th May 1993 |
| 198.137.131.0/24 | 256 | ARIN | US | 6th May 1993 |
| 198.137.132.0/24 | 256 | ARIN | US | 6th May 1993 |
| 198.137.133.0/24 | 256 | ARIN | US | 6th May 1993 |
| 198.137.134.0/24 | 256 | ARIN | US | 6th May 1993 |
| 198.137.140.0/24 | 256 | ARIN | US | 6th May 1993 |
| 198.137.141.0/24 | 256 | ARIN | US | 6th May 1993 |
| 198.137.143.0/24 | 256 | ARIN | US | 6th May 1993 |
| 198.137.144.0/24 | 256 | ARIN | US | 6th May 1993 |
| 198.137.147.0/24 | 256 | ARIN | US | 7th May 1993 |
| 198.137.154.0/24 | 256 | ARIN | US | 10th Jun 2013 |
| 198.137.155.0/24 | 256 | ARIN | US | 7th May 1993 |
| 198.137.156.0/24 | 256 | ARIN | US | 7th May 1993 |
| 198.137.157.0/24 | 256 | ARIN | US | 7th May 1993 |
| 198.137.158.0/24 | 256 | ARIN | US | 7th May 1993 |
| 198.137.159.0/24 | 256 | ARIN | US | 5th Apr 1995 |
| 198.137.160.0/24 | 256 | ARIN | US | 10th May 1993 |
| 198.137.162.0/23 | 512 | ARIN | US | 10th May 1993 |
| 198.137.164.0/23 | 512 | ARIN | US | 10th May 1993 |
| 198.137.166.0/24 | 256 | ARIN | US | 10th May 1993 |
| 198.137.168.0/24 | 256 | ARIN | US | 11th May 1993 |
| 198.137.169.0/24 | 256 | ARIN | US | 11th May 1993 |
| 198.137.170.0/24 | 256 | ARIN | US | 11th May 1993 |
| 198.137.171.0/24 | 256 | ARIN | US | 11th May 1993 |