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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 199.47.4.0/22 | 1k | ARIN |  US | 8th Nov 1993 |
| 199.47.8.0/22 | 1k | ARIN | US | 8th Nov 1993 |
| 199.48.152.0/22 | 1k | ARIN | US | 25th Oct 2010 |
| 199.48.60.0/24 | 256 | ARIN | US | 26th Dec 2024 |
| 199.5.128.0/24 | 256 | ARIN | US | 14th Dec 1993 |
| 199.5.129.0/24 | 256 | ARIN | US | 14th Dec 1993 |
| 199.5.130.0/24 | 256 | ARIN | US | 14th Dec 1993 |
| 199.5.131.0/24 | 256 | ARIN | US | 14th Dec 1993 |
| 199.5.132.0/24 | 256 | ARIN | US | 14th Dec 1993 |
| 199.5.134.0/24 | 256 | ARIN | US | 14th Dec 1993 |
| 199.5.135.0/24 | 256 | ARIN | US | 14th Dec 1993 |
| 199.5.136.0/24 | 256 | ARIN | US | 14th Dec 1993 |
| 199.5.141.0/24 | 256 | ARIN | US | 14th Dec 1993 |
| 199.5.142.0/23 | 512 | ARIN | US | 14th Dec 1993 |
| 199.5.144.0/23 | 512 | ARIN | US | 14th Dec 1993 |
| 199.5.147.0/24 | 256 | ARIN | US | 14th Aug 2015 |
| 199.5.152.0/23 | 512 | ARIN | US | 14th Dec 1993 |
| 199.5.158.0/24 | 256 | ARIN | US | 15th Dec 1993 |
| 199.5.159.0/24 | 256 | ARIN | US | 15th Dec 1993 |
| 199.5.16.0/21 | 2k | ARIN | US | 13th Sept 1993 |
| 199.5.160.0/24 | 256 | ARIN | US | 15th Dec 1993 |
| 199.5.162.0/24 | 256 | ARIN | US | 17th Dec 1993 |
| 199.5.168.0/24 | 256 | ARIN | US | 15th Dec 1993 |
| 199.5.169.0/24 | 256 | ARIN | US | 15th Dec 1993 |
| 199.5.170.0/24 | 256 | ARIN | US | 16th Dec 1993 |
| 199.5.173.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 199.5.174.0/24 | 256 | ARIN | US | 16th Dec 1993 |
| 199.5.175.0/24 | 256 | ARIN | US | 6th Jan 1994 |
| 199.5.176.0/23 | 512 | ARIN | US | 17th Dec 1993 |
| 199.5.178.0/24 | 256 | ARIN | US | 17th Dec 1993 |
| 199.5.179.0/24 | 256 | ARIN | US | 2nd Mar 2021 |
| 199.5.183.0/24 | 256 | ARIN | US | 20th Dec 1993 |
| 199.5.185.0/24 | 256 | ARIN | US | 20th Dec 1993 |
| 199.5.186.0/24 | 256 | ARIN | US | 21st Dec 1993 |
| 199.5.187.0/24 | 256 | ARIN | US | 21st Dec 1993 |
| 199.5.188.0/24 | 256 | ARIN | US | 21st Dec 1993 |
| 199.5.190.0/24 | 256 | ARIN | US | 21st Dec 1993 |
| 199.5.191.0/24 | 256 | ARIN | US | 21st Dec 1993 |
| 199.5.192.0/24 | 256 | ARIN | US | 21st Dec 1993 |
| 199.5.193.0/24 | 256 | ARIN | US | 21st Dec 1993 |
| 199.5.194.0/24 | 256 | ARIN | US | 13th Feb 2020 |
| 199.5.195.0/24 | 256 | ARIN | US | 21st Dec 1993 |
| 199.5.202.0/24 | 256 | ARIN | US | 21st Dec 1993 |
| 199.5.203.0/24 | 256 | ARIN | US | 21st Dec 1993 |
| 199.5.208.0/23 | 512 | ARIN | US | 22nd Dec 1993 |
| 199.5.212.0/24 | 256 | ARIN | US | 22nd Dec 1993 |
| 199.5.213.0/24 | 256 | ARIN | US | 22nd Dec 1993 |
| 199.5.214.0/23 | 512 | ARIN | US | 22nd Dec 1993 |
| 199.5.216.0/23 | 512 | ARIN | US | 22nd Dec 1993 |
| 199.5.218.0/24 | 256 | ARIN | US | 22nd Dec 1993 |