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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 199.181.230.0/24 | 256 | ARIN |  US | 6th Apr 1994 |
| 199.181.234.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 199.181.235.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 199.181.236.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 199.181.237.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 199.181.241.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 199.181.242.0/24 | 256 | ARIN | US | 28th May 1997 |
| 199.181.244.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 199.181.245.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 199.181.248.0/23 | 512 | ARIN | US | 11th Apr 1994 |
| 199.181.250.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 199.181.251.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 199.181.254.0/24 | 256 | ARIN | US | 11th Apr 1994 |
| 199.181.64.0/24 | 256 | ARIN | US | 20th Jul 1994 |
| 199.181.65.0/24 | 256 | ARIN | US | 20th Jul 1994 |
| 199.181.66.0/24 | 256 | ARIN | US | 20th Jul 1994 |
| 199.181.68.0/24 | 256 | ARIN | US | 20th Jul 1994 |
| 199.181.69.0/24 | 256 | ARIN | US | 20th Jul 1994 |
| 199.181.70.0/24 | 256 | ARIN | US | 20th Jul 1994 |
| 199.181.71.0/24 | 256 | ARIN | US | 20th Jul 1994 |
| 199.181.72.0/24 | 256 | ARIN | US | 21st Jul 1994 |
| 199.181.73.0/24 | 256 | ARIN | US | 21st Jul 1994 |
| 199.181.74.0/24 | 256 | ARIN | US | 21st Jul 1994 |
| 199.181.75.0/24 | 256 | ARIN | US | 21st Jul 1994 |
| 199.181.76.0/24 | 256 | ARIN | US | 21st Jul 1994 |
| 199.181.78.0/24 | 256 | ARIN | US | 21st Jul 1994 |
| 199.181.79.0/24 | 256 | ARIN | US | 21st Jul 1994 |
| 199.181.8.0/21 | 2k | ARIN | US | 7th Mar 1994 |
| 199.181.80.0/24 | 256 | ARIN | US | 21st Jul 1994 |
| 199.181.83.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.84.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.85.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.86.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.87.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.97.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.98.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.181.99.0/24 | 256 | ARIN | US | 25th Jul 1994 |
| 199.182.120.0/22 | 1k | ARIN | US | 17th Apr 2012 |
| 199.182.200.0/22 | 1k | ARIN | US | 25th Apr 2012 |
| 199.182.48.0/22 | 1k | ARIN | US | 11th Apr 2012 |
| 199.184.0.0/21 | 2k | ARIN | US | 8th Mar 1994 |
| 199.184.102.0/23 | 512 | ARIN | US | 29th Jul 1994 |
| 199.184.106.0/23 | 512 | ARIN | US | 29th Jul 1994 |
| 199.184.109.0/24 | 256 | ARIN | US | 29th Jul 1994 |
| 199.184.118.0/24 | 256 | ARIN | US | 29th Jul 1994 |
| 199.184.12.0/23 | 512 | ARIN | US | 8th Mar 1994 |
| 199.184.124.0/24 | 256 | ARIN | US | 29th Jul 1994 |
| 199.184.126.0/23 | 512 | ARIN | US | 16th Dec 2016 |
| 199.184.128.0/21 | 2k | ARIN | US | 19th Aug 2025 |
| 199.184.136.0/24 | 256 | ARIN | US | 11th Apr 1994 |