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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,356 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 205.233.203.0/24 | 256 | ARIN |  CA | 25th Apr 1995 |
| 205.233.204.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.205.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.206.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.211.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.213.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.214.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.215.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.216.0/24 | 256 | ARIN | CA | 10th Mar 2026 |
| 205.233.217.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.218.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.219.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.220.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.221.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.222.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.223.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.224.0/20 | 4.1k | ARIN | CA | 25th Apr 1995 |
| 205.233.24.0/21 | 2k | ARIN |  US | 31st Jul 2025 |
| 205.233.240.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.241.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.242.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.248.0/22 | 1k | ARIN | CA | 25th Apr 1995 |
| 205.233.252.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.253.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.254.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.255.0/24 | 256 | ARIN | US | 21st Nov 2011 |
| 205.233.32.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.34.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.36.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.37.0/24 | 256 | ARIN | CA | 17th Nov 1995 |
| 205.233.38.0/24 | 256 | ARIN | CA | 6th Jul 2026 |
| 205.233.39.0/24 | 256 | ARIN | US | 16th Nov 2011 |
| 205.233.60.0/22 | 1k | ARIN | CA | 12th Dec 1995 |
| 205.233.65.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.66.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.67.0/24 | 256 | ARIN | CA | 31st Oct 1995 |
| 205.233.68.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.69.0/24 | 256 | ARIN | CA | 8th Sept 1995 |
| 205.233.70.0/24 | 256 | ARIN | CA | 27th Dec 1995 |
| 205.233.72.0/24 | 256 | ARIN | CA | 21st Dec 1995 |
| 205.233.74.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 205.233.75.0/24 | 256 | ARIN | US | 13th Jan 2021 |
| 205.233.80.0/21 | 2k | ARIN | CA | 25th Apr 1995 |
| 205.233.88.0/23 | 512 | ARIN | CA | 25th Apr 1995 |
| 205.233.92.0/24 | 256 | ARIN | CA | 25th Apr 1995 |
| 205.233.94.0/24 | 256 | ARIN | CA | 26th Sept 1995 |
| 205.233.95.0/24 | 256 | ARIN | CA | 25th Sept 1995 |
| 205.235.144.0/20 | 4.1k | ARIN | US | 14th Jun 1995 |
| 205.235.176.0/20 | 4.1k | ARIN | US | 20th Jun 1995 |
| 205.235.240.0/20 | 4.1k | ARIN | US | 13th Jul 1995 |