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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 204.209.140.0/24 | 256 | ARIN |  CA | 11th Dec 1994 |
| 204.209.141.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.142.0/23 | 512 | ARIN | CA | 11th Dec 1994 |
| 204.209.144.0/22 | 1k | ARIN | CA | 11th Dec 1994 |
| 204.209.148.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.151.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.152.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.153.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.155.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.156.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.157.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.158.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.160.0/23 | 512 | ARIN | CA | 11th Dec 1994 |
| 204.209.167.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.168.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.169.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.172.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.173.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.174.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.175.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.178.0/23 | 512 | ARIN | CA | 11th Dec 1994 |
| 204.209.180.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.181.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.182.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.183.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.186.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.190.0/23 | 512 | ARIN | CA | 11th Dec 1994 |
| 204.209.2.0/23 | 512 | ARIN | CA | 11th Dec 1994 |
| 204.209.223.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.248.0/23 | 512 | ARIN | CA | 11th Dec 1994 |
| 204.209.250.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.254.0/24 | 256 | ARIN | CA | 7th Feb 1995 |
| 204.209.255.0/24 | 256 | ARIN |  US | 16th Jun 2017 |
| 204.209.30.0/23 | 512 | ARIN | CA | 11th Dec 1994 |
| 204.209.35.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.4.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.43.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.6.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.64.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.66.0/23 | 512 | ARIN | US | 22nd Dec 2020 |
| 204.209.7.0/24 | 256 | ARIN | CA | 11th Dec 1994 |
| 204.209.86.0/23 | 512 | ARIN | CA | 11th Dec 1994 |
| 204.209.9.0/24 | 256 | ARIN | US | 8th Oct 2025 |
| 204.209.96.0/21 | 2k | ARIN | CA | 11th Dec 1994 |
| 204.224.0.0/16 | 65.5k | ARIN | US | 5th Jan 1995 |
| 204.225.102.0/24 | 256 | ARIN | CA | 10th Jan 1995 |
| 204.225.104.0/24 | 256 | ARIN | CA | 10th Jan 1995 |
| 204.225.105.0/24 | 256 | ARIN | CA | 10th Jan 1995 |
| 204.225.108.0/22 | 1k | ARIN | CA | 10th Jan 1995 |
| 204.225.112.0/24 | 256 | ARIN | CA | 10th Jan 1995 |