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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,300 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 204.87.194.0/24 | 256 | ARIN |  US | 1st Jul 2026 |
| 204.87.195.0/24 | 256 | ARIN | US | 26th Jan 1995 |
| 204.87.196.0/24 | 256 | ARIN | US | 26th Jan 1995 |
| 204.87.197.0/24 | 256 | ARIN | US | 26th Jan 1995 |
| 204.87.199.0/24 | 256 | ARIN | US | 26th Jan 1995 |
| 204.87.200.0/24 | 256 | ARIN | US | 26th Jan 1995 |
| 204.87.201.0/24 | 256 | ARIN | US | 26th Jan 1995 |
| 204.87.202.0/24 | 256 | ARIN | US | 26th Jan 1995 |
| 204.87.206.0/24 | 256 | ARIN | US | 15th Jul 2026 |
| 204.87.207.0/24 | 256 | ARIN | US | 30th Jan 1995 |
| 204.87.208.0/24 | 256 | ARIN | US | 30th Jan 1995 |
| 204.87.209.0/24 | 256 | ARIN | US | 30th Jan 1995 |
| 204.87.210.0/24 | 256 | ARIN | US | 30th Jan 1995 |
| 204.87.214.0/24 | 256 | ARIN | US | 30th Jan 1995 |
| 204.87.215.0/24 | 256 | ARIN | US | 30th Jan 1995 |
| 204.87.216.0/24 | 256 | ARIN | US | 1st Feb 1995 |
| 204.87.217.0/24 | 256 | ARIN | US | 1st Feb 1995 |
| 204.87.218.0/24 | 256 | ARIN | US | 1st Feb 1995 |
| 204.87.219.0/24 | 256 | ARIN | US | 1st Feb 1995 |
| 204.87.220.0/24 | 256 | ARIN | US | 1st Feb 1995 |
| 204.87.221.0/24 | 256 | ARIN | US | 1st Feb 1995 |
| 204.87.222.0/24 | 256 | ARIN | US | 6th Aug 2019 |
| 204.87.223.0/24 | 256 | ARIN | US | 1st Feb 1995 |
| 204.87.224.0/24 | 256 | ARIN | US | 24th Sept 2018 |
| 204.87.228.0/24 | 256 | ARIN | US | 23rd Feb 1995 |
| 204.87.229.0/24 | 256 | ARIN | US | 23rd Feb 1995 |
| 204.87.230.0/24 | 256 | ARIN | US | 23rd Feb 1995 |
| 204.87.231.0/24 | 256 | ARIN | US | 23rd Feb 1995 |
| 204.87.232.0/24 | 256 | ARIN | US | 23rd Feb 1995 |
| 204.87.234.0/24 | 256 | ARIN | US | 24th Feb 1995 |
| 204.87.235.0/24 | 256 | ARIN | US | 22nd Aug 2023 |
| 204.87.236.0/24 | 256 | ARIN | US | 28th Feb 1995 |
| 204.87.238.0/24 | 256 | ARIN | US | 28th Feb 1995 |
| 204.87.239.0/24 | 256 | ARIN | US | 1st Mar 1995 |
| 204.87.240.0/24 | 256 | ARIN | US | 1st Mar 1995 |
| 204.87.241.0/24 | 256 | ARIN | US | 1st Mar 1995 |
| 204.87.242.0/24 | 256 | ARIN | US | 1st Mar 1995 |
| 204.87.245.0/24 | 256 | ARIN | US | 3rd Mar 1995 |
| 204.87.246.0/24 | 256 | ARIN | US | 3rd Mar 1995 |
| 204.87.247.0/24 | 256 | ARIN | US | 3rd Mar 1995 |
| 204.87.248.0/24 | 256 | ARIN | US | 3rd Mar 1995 |
| 204.87.250.0/24 | 256 | ARIN | US | 6th Mar 1995 |
| 204.87.251.0/24 | 256 | ARIN | US | 26th Sept 2018 |
| 204.87.252.0/24 | 256 | ARIN | US | 6th Mar 1995 |
| 204.87.254.0/24 | 256 | ARIN | US | 6th Mar 1995 |
| 204.88.16.0/21 | 2k | ARIN | US | 8th Aug 1994 |
| 204.88.160.0/20 | 4.1k | ARIN | US | 11th Oct 1994 |
| 204.88.190.0/23 | 512 | ARIN | US | 6th Dec 2011 |
| 204.88.24.0/22 | 1k | ARIN | US | 8th Aug 1994 |
| 204.88.32.0/19 | 8.2k | ARIN | US | 5th Jul 1994 |