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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,458 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 204.130.207.0/24 | 256 | ARIN |  US | 2nd Dec 1994 |
| 204.130.208.0/24 | 256 | ARIN | US | 2nd Dec 1994 |
| 204.130.210.0/24 | 256 | ARIN | US | 2nd Dec 1994 |
| 204.130.211.0/24 | 256 | ARIN | US | 2nd Dec 1994 |
| 204.130.212.0/24 | 256 | ARIN | US | 2nd Dec 1994 |
| 204.130.213.0/24 | 256 | ARIN | US | 2nd Dec 1994 |
| 204.130.215.0/24 | 256 | ARIN | US | 2nd Dec 1994 |
| 204.130.216.0/24 | 256 | ARIN | US | 20th Dec 1996 |
| 204.130.218.0/24 | 256 | ARIN | US | 8th Dec 1994 |
| 204.130.219.0/24 | 256 | ARIN | US | 8th Dec 1994 |
| 204.130.220.0/24 | 256 | ARIN | US | 11th Dec 1994 |
| 204.130.221.0/24 | 256 | ARIN | US | 11th Dec 1994 |
| 204.130.222.0/24 | 256 | ARIN | US | 11th Dec 1994 |
| 204.130.223.0/24 | 256 | ARIN | US | 22nd Jul 2026 |
| 204.130.225.0/24 | 256 | ARIN | US | 12th Dec 1994 |
| 204.130.227.0/24 | 256 | ARIN | US | 12th Dec 1994 |
| 204.130.229.0/24 | 256 | ARIN | US | 12th Dec 1994 |
| 204.130.230.0/24 | 256 | ARIN | US | 12th Dec 1994 |
| 204.130.231.0/24 | 256 | ARIN | US | 12th Dec 1994 |
| 204.130.232.0/24 | 256 | ARIN | US | 12th Dec 1994 |
| 204.130.233.0/24 | 256 | ARIN | US | 12th Dec 1994 |
| 204.130.234.0/24 | 256 | ARIN | US | 12th Dec 1994 |
| 204.130.235.0/24 | 256 | ARIN | US | 12th Dec 1994 |
| 204.130.236.0/24 | 256 | ARIN | US | 12th Dec 1994 |
| 204.130.237.0/24 | 256 | ARIN | US | 12th Dec 1994 |
| 204.130.239.0/24 | 256 | ARIN | US | 15th Dec 1994 |
| 204.130.241.0/24 | 256 | ARIN | US | 15th Dec 1994 |
| 204.130.242.0/24 | 256 | ARIN | US | 15th Dec 1994 |
| 204.130.243.0/24 | 256 | ARIN | US | 16th Dec 1994 |
| 204.130.244.0/24 | 256 | ARIN | US | 21st Dec 2016 |
| 204.130.245.0/24 | 256 | ARIN | US | 19th Dec 1994 |
| 204.130.246.0/24 | 256 | ARIN | US | 19th Dec 1994 |
| 204.130.247.0/24 | 256 | ARIN | US | 19th Dec 1994 |
| 204.130.248.0/24 | 256 | ARIN | US | 20th Dec 1994 |
| 204.130.250.0/24 | 256 | ARIN | US | 20th Dec 1994 |
| 204.130.251.0/24 | 256 | ARIN | US | 20th Dec 1994 |
| 204.130.252.0/24 | 256 | ARIN | US | 20th Dec 1994 |
| 204.130.254.0/24 | 256 | ARIN | US | 20th Dec 1994 |
| 204.130.32.0/19 | 8.2k | ARIN | US | 20th Dec 1994 |
| 204.136.8.0/23 | 512 | ARIN | US | 29th Aug 1994 |
| 204.137.12.0/24 | 256 | ARIN | US | 3rd Apr 2024 |
| 204.137.16.0/21 | 2k | ARIN | US | 17th Feb 2026 |
| 204.137.24.0/23 | 512 | RIPE NCC |  GB | 29th Aug 1994 |
| 204.137.8.0/22 | 1k | ARIN | US | 12th Feb 2026 |
| 204.138.0.0/24 | 256 | ARIN |  PR | 9th Jun 2020 |
| 204.138.1.0/24 | 256 | ARIN |  CA | 30th Aug 1994 |
| 204.138.100.0/23 | 512 | ARIN | US | 5th Jan 2011 |
| 204.138.103.0/24 | 256 | ARIN | CA | 17th Apr 1995 |
| 204.138.105.0/24 | 256 | ARIN | CA | 30th Aug 1994 |
| 204.138.112.0/24 | 256 | ARIN | US | 10th Jan 2011 |