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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 the most unannounced blocks, largest first.
Unannounced blocks in United States
27,034 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 199.127.24.0/22 | 1k | ARIN |  US | 18th Nov 1993 |
| 199.127.28.0/23 | 512 | ARIN | US | 18th Nov 1993 |
| 199.127.30.0/24 | 256 | ARIN | US | 18th Nov 1993 |
| 199.127.57.0/24 | 256 | ARIN | US | 18th Dec 2025 |
| 199.127.58.0/24 | 256 | ARIN | US | 9th Dec 2025 |
| 199.127.64.0/22 | 1k | ARIN | US | 15th Mar 2012 |
| 199.127.72.0/21 | 2k | ARIN | US | 22nd Nov 2024 |
| 199.127.80.0/22 | 1k | ARIN | US | 1st Jul 2026 |
| 199.127.84.0/22 | 1k | ARIN | US | 1st Jul 2026 |
| 199.15.152.0/21 | 2k | ARIN | US | 25th Jun 2010 |
| 199.15.16.0/21 | 2k | ARIN | US | 28th Sept 1993 |
| 199.15.176.0/22 | 1k | ARIN | US | 29th Jun 2010 |
| 199.15.188.0/22 | 1k | ARIN | US | 30th Jun 2010 |
| 199.15.24.0/23 | 512 | ARIN | US | 28th Sept 1993 |
| 199.15.32.0/19 | 8.2k | ARIN | US | 27th Sept 1993 |
| 199.15.64.0/21 | 2k | ARIN | US | 8th Mar 1994 |
| 199.15.8.0/21 | 2k | ARIN | US | 28th Sept 1993 |
| 199.15.88.0/24 | 256 | ARIN | US | 14th May 2008 |
| 199.16.107.0/24 | 256 | ARIN | US | 21st Mar 2025 |
| 199.16.136.0/21 | 2k | ARIN | US | 8th Jul 2010 |
| 199.16.16.0/21 | 2k | ARIN | US | 30th Sept 1993 |
| 199.16.224.0/21 | 2k | ARIN | US | 19th Jul 2010 |
| 199.16.232.0/22 | 1k | ARIN | US | 19th Jul 2010 |
| 199.16.24.0/22 | 1k | ARIN | US | 30th Sept 1993 |
| 199.16.28.0/23 | 512 | ARIN | US | 30th Sept 1993 |
| 199.164.0.0/21 | 2k | ARIN | US | 9th Feb 1994 |
| 199.164.128.0/24 | 256 | ARIN | US | 10th Mar 1994 |
| 199.164.130.0/23 | 512 | ARIN | US | 10th Mar 1994 |
| 199.164.132.0/24 | 256 | ARIN | US | 10th Mar 1994 |
| 199.164.133.0/24 | 256 | ARIN | US | 10th Mar 1994 |
| 199.164.134.0/24 | 256 | ARIN | US | 11th Mar 1994 |
| 199.164.137.0/24 | 256 | ARIN | US | 11th Mar 1994 |
| 199.164.139.0/24 | 256 | ARIN | US | 11th Mar 1994 |
| 199.164.140.0/24 | 256 | ARIN | US | 11th Mar 1994 |
| 199.164.144.0/24 | 256 | ARIN | US | 14th Mar 1994 |
| 199.164.145.0/24 | 256 | ARIN | US | 14th Mar 1994 |
| 199.164.146.0/24 | 256 | ARIN | US | 14th Mar 1994 |
| 199.164.148.0/24 | 256 | ARIN | US | 14th Mar 1994 |
| 199.164.150.0/23 | 512 | ARIN | US | 14th Mar 1994 |
| 199.164.152.0/24 | 256 | ARIN | US | 14th Mar 1994 |
| 199.164.153.0/24 | 256 | ARIN | US | 14th Mar 1994 |
| 199.164.154.0/24 | 256 | ARIN | US | 14th Mar 1994 |
| 199.164.156.0/24 | 256 | ARIN | US | 14th Mar 1994 |
| 199.164.157.0/24 | 256 | ARIN | US | 14th Mar 1994 |
| 199.164.158.0/24 | 256 | ARIN | US | 14th Mar 1994 |
| 199.164.162.0/24 | 256 | ARIN | US | 14th Mar 1994 |
| 199.164.164.0/24 | 256 | ARIN | US | 14th Mar 1994 |
| 199.164.168.0/23 | 512 | ARIN | US | 15th Mar 1994 |
| 199.164.170.0/23 | 512 | ARIN | US | 15th Mar 1994 |
| 199.164.172.0/24 | 256 | ARIN | US | 15th Mar 1994 |