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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 192.88.150.0/24 | 256 | ARIN |  US | 20th Dec 1990 |
| 192.88.151.0/24 | 256 | ARIN | US | 20th Dec 1990 |
| 192.88.152.0/24 | 256 | ARIN | US | 20th Dec 1990 |
| 192.88.153.0/24 | 256 | ARIN | US | 20th Dec 1990 |
| 192.88.154.0/24 | 256 | ARIN | US | 20th Dec 1990 |
| 192.88.156.0/22 | 1k | ARIN | US | 20th Dec 1990 |
| 192.88.160.0/20 | 4.1k | ARIN | US | 20th Dec 1990 |
| 192.88.176.0/24 | 256 | ARIN | US | 20th Dec 1990 |
| 192.88.177.0/24 | 256 | ARIN | US | 20th Dec 1990 |
| 192.88.184.0/24 | 256 | ARIN | US | 20th Dec 1990 |
| 192.88.185.0/24 | 256 | ARIN | US | 20th Dec 1990 |
| 192.88.186.0/24 | 256 | ARIN | US | 4th Feb 2015 |
| 192.88.188.0/24 | 256 | ARIN | US | 20th Dec 1990 |
| 192.88.197.0/24 | 256 | ARIN | US | 2nd Jan 1991 |
| 192.88.2.0/24 | 256 | ARIN | US | 28th Nov 1990 |
| 192.88.200.0/24 | 256 | ARIN | US | 15th Jan 1991 |
| 192.88.203.0/24 | 256 | ARIN | US | 15th Jan 1991 |
| 192.88.206.0/24 | 256 | ARIN | US | 15th Jan 1991 |
| 192.88.207.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.208.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.211.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.213.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.214.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.215.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.216.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.217.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.22.0/24 | 256 | ARIN | US | 5th Dec 1990 |
| 192.88.220.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.221.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.222.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.223.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.224.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.225.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.226.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.227.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.228.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.229.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.230.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.231.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.232.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.233.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.234.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.235.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.237.0/24 | 256 | ARIN | US | 17th Jan 1991 |
| 192.88.241.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.243.0/24 | 256 | ARIN | US | 28th May 2025 |
| 192.88.244.0/24 | 256 | ARIN | US | 11th Jan 1991 |
| 192.88.245.0/24 | 256 | ARIN | US | 15th Jan 1991 |
| 192.88.246.0/23 | 512 | ARIN | US | 15th Jan 1991 |
| 192.88.28.0/24 | 256 | ARIN | US | 12th Dec 1990 |