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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
Browse by country
Countries with the most unannounced blocks, largest first.
Unannounced blocks
85,458 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 204.17.145.0/24 | 256 | ARIN |  US | 9th Jun 1994 |
| 204.17.148.0/24 | 256 | ARIN | US | 9th Jun 1994 |
| 204.17.149.0/24 | 256 | ARIN | US | 9th Jun 1994 |
| 204.17.151.0/24 | 256 | ARIN | US | 9th Jun 1994 |
| 204.17.152.0/24 | 256 | ARIN | US | 10th Jun 1994 |
| 204.17.153.0/24 | 256 | ARIN | US | 13th Jun 1994 |
| 204.17.154.0/24 | 256 | ARIN |  CA | 7th Jan 2011 |
| 204.17.155.0/24 | 256 | ARIN | US | 13th Jun 1994 |
| 204.17.156.0/24 | 256 | ARIN | US | 13th Jun 1994 |
| 204.17.164.0/24 | 256 | ARIN | US | 13th Jun 1994 |
| 204.17.165.0/24 | 256 | ARIN | US | 13th Jun 1994 |
| 204.17.166.0/24 | 256 | ARIN | US | 13th Jun 1994 |
| 204.17.167.0/24 | 256 | ARIN | US | 13th Jun 1994 |
| 204.17.168.0/24 | 256 | ARIN | US | 14th Jun 1994 |
| 204.17.170.0/23 | 512 | ARIN | US | 14th Jun 1994 |
| 204.17.172.0/22 | 1k | ARIN | US | 14th Jun 1994 |
| 204.17.180.0/24 | 256 | ARIN | US | 14th Jun 1994 |
| 204.17.181.0/24 | 256 | ARIN | US | 14th Jun 1994 |
| 204.17.182.0/24 | 256 | ARIN | US | 15th Jun 1994 |
| 204.17.183.0/24 | 256 | ARIN | US | 15th Jun 1994 |
| 204.17.184.0/24 | 256 | ARIN | US | 15th Jun 1994 |
| 204.17.185.0/24 | 256 | ARIN | US | 15th Jun 1994 |
| 204.17.186.0/24 | 256 | ARIN | US | 15th Jun 1994 |
| 204.17.188.0/24 | 256 | ARIN | US | 15th Jun 1994 |
| 204.17.189.0/24 | 256 | ARIN | US | 15th Jun 1994 |
| 204.17.190.0/23 | 512 | ARIN | US | 15th Jun 1994 |
| 204.17.192.0/24 | 256 | ARIN | US | 15th Jun 1994 |
| 204.17.193.0/24 | 256 | ARIN | US | 15th Jun 1994 |
| 204.17.194.0/24 | 256 | ARIN | US | 15th Jun 1994 |
| 204.17.198.0/23 | 512 | ARIN | US | 15th Jun 1994 |
| 204.17.200.0/24 | 256 | ARIN | US | 15th Jun 1994 |
| 204.17.201.0/24 | 256 | ARIN | US | 15th Jun 1994 |
| 204.17.202.0/23 | 512 | ARIN | US | 16th Jun 1994 |
| 204.17.208.0/24 | 256 | ARIN | US | 16th Jun 1994 |
| 204.17.209.0/24 | 256 | ARIN | US | 16th Jun 1994 |
| 204.17.210.0/24 | 256 | ARIN | US | 16th Jun 1994 |
| 204.17.211.0/24 | 256 | ARIN | US | 16th Jun 1994 |
| 204.17.212.0/24 | 256 | ARIN | US | 16th Jun 1994 |
| 204.17.213.0/24 | 256 | ARIN | US | 16th Jun 1994 |
| 204.17.214.0/24 | 256 | ARIN | US | 16th Jun 1994 |
| 204.17.215.0/24 | 256 | ARIN | US | 11th Oct 2000 |
| 204.17.216.0/24 | 256 | ARIN | US | 16th Jun 1994 |
| 204.17.217.0/24 | 256 | ARIN | US | 16th Jun 1994 |
| 204.17.218.0/24 | 256 | ARIN | US | 16th Jun 1994 |
| 204.17.220.0/24 | 256 | ARIN | US | 16th Jun 1994 |
| 204.17.221.0/24 | 256 | ARIN | US | 16th Jun 1994 |
| 204.17.222.0/24 | 256 | ARIN | US | 17th Jun 1994 |
| 204.17.223.0/24 | 256 | ARIN | US | 17th Jun 1994 |
| 204.17.224.0/24 | 256 | ARIN | US | 17th Jun 1994 |
| 204.17.225.0/24 | 256 | ARIN | US | 17th Jun 1994 |