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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,283 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.107.3.0/24 | 256 | ARIN |  US | 24th Apr 1991 |
| 192.107.32.0/23 | 512 | ARIN | US | 30th Apr 1991 |
| 192.107.34.0/24 | 256 | ARIN | US | 30th Apr 1991 |
| 192.107.35.0/24 | 256 | ARIN | US | 30th Apr 1991 |
| 192.107.36.0/24 | 256 | ARIN | US | 30th Apr 1991 |
| 192.107.37.0/24 | 256 | ARIN | US | 30th Apr 1991 |
| 192.107.40.0/24 | 256 | ARIN | US | 30th Apr 1991 |
| 192.107.42.0/24 | 256 | ARIN | US | 2nd May 1991 |
| 192.107.48.0/24 | 256 | ARIN | US | 3rd May 1991 |
| 192.107.49.0/24 | 256 | ARIN | US | 2nd Jul 2025 |
| 192.107.6.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 192.107.7.0/24 | 256 | ARIN | US | 30th Apr 1991 |
| 192.107.8.0/24 | 256 | ARIN | US | 30th Apr 1991 |
| 192.108.1.0/24 | 256 | ARIN | US | 26th Apr 1991 |
| 192.108.102.0/24 | 256 | ARIN | US | 7th Mar 1996 |
| 192.108.103.0/24 | 256 | ARIN | US | 10th May 1991 |
| 192.108.109.0/24 | 256 | ARIN | US | 22nd Jul 1991 |
| 192.108.110.0/24 | 256 | ARIN | US | 22nd Jul 1991 |
| 192.108.111.0/24 | 256 | ARIN | US | 22nd Jul 1991 |
| 192.108.112.0/24 | 256 | ARIN | US | 22nd Jul 1991 |
| 192.108.122.0/24 | 256 | ARIN | US | 24th Jul 1991 |
| 192.108.123.0/24 | 256 | ARIN | US | 13th Sept 1996 |
| 192.108.127.0/24 | 256 | ARIN | US | 12th Mar 2015 |
| 192.108.17.0/24 | 256 | ARIN | US | 29th Apr 1991 |
| 192.108.18.0/24 | 256 | ARIN | US | 29th Apr 1991 |
| 192.108.186.0/24 | 256 | ARIN | US | 24th Jul 1991 |
| 192.108.187.0/24 | 256 | ARIN | US | 24th Jul 1991 |
| 192.108.189.0/24 | 256 | ARIN | US | 24th Jul 1991 |
| 192.108.192.0/23 | 512 | ARIN | US | 24th Jul 1991 |
| 192.108.194.0/24 | 256 | ARIN | US | 24th Jul 1991 |
| 192.108.2.0/24 | 256 | ARIN | US | 26th Apr 1991 |
| 192.108.20.0/24 | 256 | ARIN | US | 3rd Oct 1994 |
| 192.108.21.0/24 | 256 | ARIN | US | 29th Apr 1991 |
| 192.108.215.0/24 | 256 | ARIN | US | 31st Jul 1991 |
| 192.108.216.0/24 | 256 | ARIN | US | 1st Aug 1991 |
| 192.108.217.0/24 | 256 | ARIN | US | 1st Aug 1991 |
| 192.108.218.0/24 | 256 | ARIN | US | 1st Aug 1991 |
| 192.108.219.0/24 | 256 | ARIN | US | 1st Aug 1991 |
| 192.108.22.0/24 | 256 | ARIN | US | 1st May 1991 |
| 192.108.220.0/24 | 256 | ARIN | US | 1st Aug 1991 |
| 192.108.222.0/24 | 256 | ARIN | US | 21st Sept 1992 |
| 192.108.223.0/24 | 256 | ARIN | US | 30th Jul 1993 |
| 192.108.226.0/24 | 256 | ARIN | US | 1st Aug 1991 |
| 192.108.228.0/24 | 256 | ARIN | US | 2nd Aug 1991 |
| 192.108.229.0/24 | 256 | ARIN | US | 2nd Aug 1991 |
| 192.108.233.0/24 | 256 | ARIN | US | 2nd Aug 1991 |
| 192.108.236.0/24 | 256 | ARIN | US | 5th Aug 1991 |
| 192.108.237.0/24 | 256 | ARIN | US | 5th Aug 1991 |
| 192.108.239.0/24 | 256 | ARIN | US | 18th Sept 2015 |
| 192.108.240.0/23 | 512 | ARIN | US | 5th Aug 1991 |