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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks registered through ARIN
30,441 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.16.205.0/24 | 256 | ARIN |  CA | 29th Mar 1989 |
| 192.16.206.0/24 | 256 | ARIN | CA | 29th Mar 1989 |
| 192.16.207.0/24 | 256 | ARIN | CA | 19th Jul 1989 |
| 192.16.208.0/24 | 256 | ARIN | CA | 19th Jul 1989 |
| 192.16.209.0/24 | 256 | ARIN | CA | 21st Nov 1988 |
| 192.16.210.0/24 | 256 | ARIN | CA | 21st Nov 1988 |
| 192.16.211.0/24 | 256 | ARIN | CA | 21st Nov 1988 |
| 192.16.212.0/24 | 256 | ARIN | CA | 21st Nov 1988 |
| 192.16.213.0/24 | 256 | ARIN | CA | 21st Nov 1988 |
| 192.16.214.0/24 | 256 | ARIN | CA | 21st Nov 1988 |
| 192.16.215.0/24 | 256 | ARIN | CA | 21st Nov 1988 |
| 192.16.216.0/24 | 256 | ARIN | CA | 21st Nov 1988 |
| 192.16.217.0/24 | 256 | ARIN | CA | 21st Nov 1988 |
| 192.16.218.0/24 | 256 | ARIN | CA | 21st Nov 1988 |
| 192.16.219.0/24 | 256 | ARIN | CA | 14th Mar 1991 |
| 192.16.220.0/24 | 256 | ARIN | CA | 14th Mar 1991 |
| 192.16.221.0/24 | 256 | ARIN | CA | 14th Mar 1991 |
| 192.16.222.0/24 | 256 | ARIN | CA | 14th Mar 1991 |
| 192.16.223.0/24 | 256 | ARIN | CA | 14th Mar 1991 |
| 192.16.224.0/24 | 256 | ARIN | CA | 14th Mar 1991 |
| 192.16.225.0/24 | 256 | ARIN | CA | 14th Mar 1991 |
| 192.16.226.0/24 | 256 | ARIN | CA | 14th Mar 1991 |
| 192.16.227.0/24 | 256 | ARIN | CA | 14th Mar 1991 |
| 192.16.228.0/24 | 256 | ARIN | CA | 14th Mar 1991 |
| 192.16.229.0/24 | 256 | ARIN | CA | 14th Mar 1991 |
| 192.16.230.0/24 | 256 | ARIN | CA | 14th Mar 1991 |
| 192.16.231.0/24 | 256 | ARIN | CA | 14th Mar 1991 |
| 192.16.232.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.233.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.234.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.235.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.236.0/24 | 256 | ARIN | CA | 29th Oct 1992 |
| 192.16.237.0/24 | 256 | ARIN | CA | 29th Oct 1992 |
| 192.16.238.0/24 | 256 | ARIN | CA | 29th Oct 1992 |
| 192.16.239.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.240.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.241.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.242.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.243.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.244.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.245.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.246.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.247.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.248.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.249.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.252.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.253.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.254.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.255.0/24 | 256 | ARIN | CA | 30th Dec 1991 |
| 192.16.64.0/21 | 2k | ARIN |  US | 5th Nov 2012 |