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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,300 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 205.159.160.0/24 | 256 | ARIN |  US | 29th Aug 1995 |
| 205.159.161.0/24 | 256 | ARIN | US | 29th Aug 1995 |
| 205.159.162.0/24 | 256 | ARIN | US | 29th Aug 1995 |
| 205.159.163.0/24 | 256 | ARIN | US | 29th Aug 1995 |
| 205.159.164.0/24 | 256 | ARIN | US | 29th Aug 1995 |
| 205.159.165.0/24 | 256 | ARIN | US | 30th Aug 1995 |
| 205.159.166.0/24 | 256 | ARIN | US | 30th Aug 1995 |
| 205.159.167.0/24 | 256 | ARIN | US | 30th Aug 1995 |
| 205.159.168.0/24 | 256 | ARIN | US | 30th Aug 1995 |
| 205.159.17.0/24 | 256 | ARIN | US | 10th Mar 1995 |
| 205.159.170.0/24 | 256 | ARIN | US | 30th Aug 1995 |
| 205.159.171.0/24 | 256 | ARIN | US | 30th Aug 1995 |
| 205.159.172.0/24 | 256 | ARIN | US | 30th Aug 1995 |
| 205.159.173.0/24 | 256 | ARIN | US | 30th Aug 1995 |
| 205.159.174.0/24 | 256 | ARIN | US | 29th Sept 1995 |
| 205.159.175.0/24 | 256 | ARIN | US | 30th Aug 1995 |
| 205.159.176.0/24 | 256 | ARIN | US | 31st Aug 1995 |
| 205.159.177.0/24 | 256 | ARIN | US | 31st Aug 1995 |
| 205.159.179.0/24 | 256 | ARIN | US | 31st Aug 1995 |
| 205.159.18.0/24 | 256 | ARIN | US | 10th Mar 1995 |
| 205.159.181.0/24 | 256 | ARIN | US | 31st Aug 1995 |
| 205.159.182.0/24 | 256 | ARIN | US | 1st Sept 1995 |
| 205.159.183.0/24 | 256 | ARIN | US | 1st Sept 1995 |
| 205.159.184.0/24 | 256 | ARIN | US | 1st Sept 1995 |
| 205.159.185.0/24 | 256 | ARIN | US | 1st Sept 1995 |
| 205.159.186.0/24 | 256 | ARIN | US | 1st Sept 1995 |
| 205.159.187.0/24 | 256 | ARIN | US | 6th Sept 1995 |
| 205.159.19.0/24 | 256 | ARIN | US | 10th Mar 1995 |
| 205.159.190.0/24 | 256 | ARIN | US | 7th Sept 1995 |
| 205.159.191.0/24 | 256 | ARIN | US | 7th Sept 1995 |
| 205.159.192.0/24 | 256 | ARIN | US | 7th Sept 1995 |
| 205.159.195.0/24 | 256 | ARIN | US | 11th Sept 1995 |
| 205.159.196.0/24 | 256 | ARIN | US | 11th Sept 1995 |
| 205.159.197.0/24 | 256 | ARIN | US | 11th Sept 1995 |
| 205.159.198.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 205.159.199.0/24 | 256 | ARIN | US | 11th Sept 1995 |
| 205.159.2.0/24 | 256 | ARIN | US | 9th Mar 1995 |
| 205.159.20.0/24 | 256 | ARIN | US | 10th Mar 1995 |
| 205.159.200.0/24 | 256 | ARIN | US | 11th Sept 1995 |
| 205.159.201.0/24 | 256 | ARIN | US | 11th Sept 1995 |
| 205.159.202.0/24 | 256 | ARIN | US | 11th Sept 1995 |
| 205.159.203.0/24 | 256 | ARIN | US | 11th Sept 1995 |
| 205.159.204.0/24 | 256 | ARIN | US | 11th Sept 1995 |
| 205.159.205.0/24 | 256 | ARIN | US | 11th Sept 1995 |
| 205.159.206.0/24 | 256 | ARIN | US | 11th Sept 1995 |
| 205.159.207.0/24 | 256 | ARIN | US | 11th Sept 1995 |
| 205.159.208.0/24 | 256 | ARIN | US | 20th Nov 2017 |
| 205.159.209.0/24 | 256 | ARIN | US | 11th Sept 1995 |
| 205.159.210.0/24 | 256 | ARIN | US | 14th Sept 1995 |
| 205.159.211.0/24 | 256 | ARIN | US | 14th Sept 1995 |