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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,283 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.12.24.0/24 | 256 | ARIN |  US | 8th Oct 1984 |
| 192.12.243.0/24 | 256 | ARIN | US | 11th Mar 1986 |
| 192.12.246.0/24 | 256 | ARIN | US | 11th Mar 1986 |
| 192.12.248.0/24 | 256 | ARIN | US | 18th Dec 1987 |
| 192.12.249.0/24 | 256 | ARIN | US | 18th Dec 1987 |
| 192.12.25.0/24 | 256 | ARIN | US | 8th Oct 1984 |
| 192.12.251.0/24 | 256 | ARIN | US | 18th Jan 1988 |
| 192.12.252.0/24 | 256 | ARIN | US | 14th Mar 1986 |
| 192.12.253.0/24 | 256 | ARIN | US | 14th Mar 1986 |
| 192.12.254.0/24 | 256 | ARIN | US | 14th Mar 1986 |
| 192.12.255.0/24 | 256 | ARIN | US | 14th Mar 1986 |
| 192.12.27.0/24 | 256 | ARIN | US | 18th Oct 1984 |
| 192.12.3.0/24 | 256 | ARIN | US | 11th Jun 1984 |
| 192.12.36.0/22 | 1k | ARIN | US | 9th Jan 1985 |
| 192.12.4.0/24 | 256 | ARIN | US | 11th Jun 1984 |
| 192.12.42.0/24 | 256 | ARIN | US | 9th Jan 1985 |
| 192.12.44.0/24 | 256 | ARIN | US | 29th Jan 1985 |
| 192.12.45.0/24 | 256 | ARIN | US | 13th Aug 2026 |
| 192.12.48.0/24 | 256 | ARIN | US | 28th Feb 1985 |
| 192.12.49.0/24 | 256 | ARIN | US | 28th Feb 1985 |
| 192.12.50.0/24 | 256 | ARIN | US | 28th Feb 1985 |
| 192.12.53.0/24 | 256 | ARIN | US | 22nd Mar 1985 |
| 192.12.56.0/24 | 256 | ARIN | US | 9th Apr 1985 |
| 192.12.57.0/24 | 256 | ARIN | US | 11th Apr 1985 |
| 192.12.58.0/24 | 256 | ARIN | US | 11th Apr 1985 |
| 192.12.59.0/24 | 256 | ARIN | US | 11th Apr 1985 |
| 192.12.60.0/24 | 256 | ARIN | US | 11th Apr 1985 |
| 192.12.61.0/24 | 256 | ARIN | US | 11th Apr 1985 |
| 192.12.64.0/24 | 256 | ARIN | US | 22nd Apr 1985 |
| 192.12.74.0/24 | 256 | ARIN | US | 7th Jun 1985 |
| 192.12.75.0/24 | 256 | ARIN | US | 24th Jun 1985 |
| 192.12.93.0/24 | 256 | ARIN | US | 13th Nov 1987 |
| 192.12.97.0/24 | 256 | ARIN | US | 1st Nov 1989 |
| 192.120.1.0/24 | 256 | ARIN | US | 2nd Aug 1991 |
| 192.120.104.0/23 | 512 | ARIN | US | 2nd Aug 1991 |
| 192.120.106.0/23 | 512 | ARIN | US | 2nd Aug 1991 |
| 192.120.108.0/22 | 1k | ARIN | US | 2nd Aug 1991 |
| 192.120.112.0/21 | 2k | ARIN | US | 2nd Aug 1991 |
| 192.120.120.0/24 | 256 | ARIN | US | 2nd Aug 1991 |
| 192.120.121.0/24 | 256 | ARIN | US | 2nd Aug 1991 |
| 192.120.122.0/23 | 512 | ARIN | US | 2nd Aug 1991 |
| 192.120.128.0/18 | 16.4k | ARIN | US | 2nd Aug 1991 |
| 192.120.16.0/20 | 4.1k | ARIN | US | 2nd Aug 1991 |
| 192.120.192.0/24 | 256 | ARIN | US | 2nd Aug 1991 |
| 192.120.193.0/24 | 256 | ARIN | US | 2nd Aug 1991 |
| 192.120.194.0/23 | 512 | ARIN | US | 2nd Aug 1991 |
| 192.120.2.0/23 | 512 | ARIN | US | 2nd Aug 1991 |
| 192.120.200.0/21 | 2k | ARIN | US | 2nd Aug 1991 |
| 192.120.212.0/24 | 256 | ARIN | US | 2nd Aug 1991 |
| 192.120.213.0/24 | 256 | ARIN | US | 2nd Aug 1991 |