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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,315 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 198.51.47.0/24 | 256 | ARIN |  US | 28th Jan 1993 |
| 198.51.48.0/24 | 256 | ARIN | US | 28th Jan 1993 |
| 198.51.53.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.54.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 198.51.56.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 198.51.58.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.59.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.60.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.62.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.63.0/24 | 256 | ARIN | US | 10th Sept 2013 |
| 198.51.64.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.65.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.66.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.67.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.68.0/24 | 256 | ARIN | US | 23rd Mar 1994 |
| 198.51.69.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.70.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.73.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.74.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.77.0/24 | 256 | ARIN | US | 17th Jul 1996 |
| 198.51.78.0/23 | 512 | ARIN | US | 17th Jul 1996 |
| 198.51.80.0/23 | 512 | ARIN | US | 17th Jul 1996 |
| 198.51.89.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.51.90.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 198.52.16.0/21 | 2k | ARIN | US | 28th Jan 1993 |
| 198.52.24.0/23 | 512 | ARIN | US | 28th Jan 1993 |
| 198.52.32.0/23 | 512 | ARIN | US | 22nd Feb 2016 |
| 198.52.34.0/23 | 512 | ARIN | US | 20th Aug 2026 |
| 198.52.37.0/24 | 256 | ARIN | US | 17th Jun 2026 |
| 198.52.38.0/24 | 256 | ARIN | US | 8th Jun 2026 |
| 198.52.39.0/24 | 256 | ARIN | US | 6th Jul 2026 |
| 198.52.4.0/22 | 1k | ARIN | US | 8th Feb 1993 |
| 198.52.41.0/24 | 256 | ARIN | US | 3rd Aug 2016 |
| 198.54.0.0/24 | 256 | ARIN | US | 24th Sept 2013 |
| 198.54.152.0/23 | 512 | ARIN | US | 26th Jul 2021 |
| 198.54.164.0/24 | 256 | ARIN | US | 26th Sept 2013 |
| 198.54.235.0/24 | 256 | ARIN | US | 8th Oct 2013 |
| 198.55.128.0/18 | 16.4k | ARIN | US | 15th Oct 1993 |
| 198.55.92.0/23 | 512 | ARIN | US | 10th Feb 1993 |
| 198.56.32.0/20 | 4.1k | ARIN | US | 4th Feb 1993 |
| 198.56.48.0/22 | 1k | ARIN | US | 4th Feb 1993 |
| 198.56.64.0/18 | 16.4k | ARIN | US | 2nd Feb 1993 |
| 198.57.16.0/21 | 2k | ARIN | US | 5th Feb 1993 |
| 198.57.24.0/23 | 512 | ARIN | US | 5th Feb 1993 |
| 198.58.13.0/24 | 256 | ARIN | US | 13th Feb 2020 |
| 198.58.32.0/22 | 1k | ARIN | US | 8th Mar 1993 |
| 198.58.36.0/23 | 512 | ARIN | US | 8th Mar 1993 |
| 198.58.38.0/24 | 256 | ARIN | US | 8th Mar 1993 |
| 198.58.39.0/24 | 256 | ARIN | US | 13th Nov 2013 |
| 198.58.6.0/24 | 256 | ARIN | US | 9th Feb 1993 |