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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,392 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 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 |
| 204.89.0.0/21 | 2k | ARIN | US | 6th Jul 1994 |
| 204.89.130.0/24 | 256 | ARIN | US | 12th Sept 1994 |
| 204.89.137.0/24 | 256 | ARIN | US | 13th Sept 1994 |
| 204.89.140.0/24 | 256 | ARIN | US | 14th Jul 1994 |
| 204.89.141.0/24 | 256 | ARIN | US | 13th Sept 1994 |
| 204.89.144.0/24 | 256 | ARIN | US | 13th Sept 1994 |
| 204.89.145.0/24 | 256 | ARIN | US | 13th Sept 1994 |
| 204.89.146.0/24 | 256 | ARIN | US | 13th Sept 1994 |
| 204.89.155.0/24 | 256 | ARIN | US | 13th Sept 1994 |
| 204.89.156.0/23 | 512 | ARIN | US | 15th Sept 1994 |
| 204.89.162.0/24 | 256 | ARIN | US | 15th Sept 1994 |
| 204.89.163.0/24 | 256 | ARIN | US | 15th Sept 1994 |
| 204.89.164.0/22 | 1k | ARIN | US | 15th Sept 1994 |
| 204.89.168.0/24 | 256 | ARIN | US | 15th Sept 1994 |
| 204.89.171.0/24 | 256 | ARIN | US | 15th Sept 1994 |
| 204.89.172.0/24 | 256 | ARIN | US | 15th Sept 1994 |
| 204.89.173.0/24 | 256 | ARIN | US | 16th Sept 1994 |
| 204.89.174.0/23 | 512 | ARIN | US | 16th Sept 1994 |
| 204.89.176.0/22 | 1k | ARIN | US | 16th Sept 1994 |
| 204.89.180.0/24 | 256 | ARIN | US | 16th Sept 1994 |
| 204.89.182.0/24 | 256 | ARIN | US | 16th Sept 1994 |
| 204.89.183.0/24 | 256 | ARIN | US | 16th Sept 1994 |
| 204.89.184.0/24 | 256 | ARIN | US | 16th Sept 1994 |
| 204.89.185.0/24 | 256 | ARIN | US | 16th Sept 1994 |
| 204.89.187.0/24 | 256 | ARIN | US | 16th Sept 1994 |
| 204.89.190.0/24 | 256 | ARIN | US | 16th Sept 1994 |
| 204.89.191.0/24 | 256 | ARIN | US | 16th Sept 1994 |
| 204.89.193.0/24 | 256 | ARIN | US | 16th Sept 1994 |
| 204.89.194.0/24 | 256 | ARIN | US | 16th Sept 1994 |
| 204.89.195.0/24 | 256 | ARIN | US | 17th Sept 1994 |
| 204.89.197.0/24 | 256 | ARIN | US | 17th Sept 1994 |
| 204.89.199.0/24 | 256 | ARIN | US | 17th Sept 1994 |
| 204.89.20.0/23 | 512 | ARIN | US | 24th Oct 2017 |
| 204.89.200.0/24 | 256 | ARIN | US | 17th Sept 1994 |
| 204.89.201.0/24 | 256 | ARIN | US | 17th Sept 1994 |
| 204.89.202.0/24 | 256 | ARIN | US | 17th Sept 1994 |