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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
30,463 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 198.181.151.0/24 | 256 | ARIN |  US | 24th Nov 1993 |
| 198.181.152.0/24 | 256 | ARIN | US | 24th Nov 1993 |
| 198.181.153.0/24 | 256 | ARIN | US | 29th May 2026 |
| 198.181.154.0/24 | 256 | ARIN | US | 23rd Mar 2026 |
| 198.181.155.0/24 | 256 | ARIN | US | 24th Nov 1993 |
| 198.181.156.0/24 | 256 | ARIN | US | 24th Nov 1993 |
| 198.181.157.0/24 | 256 | ARIN | US | 24th Nov 1993 |
| 198.181.158.0/24 | 256 | ARIN | US | 24th Nov 1993 |
| 198.181.159.0/24 | 256 | ARIN | US | 7th Feb 2013 |
| 198.181.160.0/24 | 256 | ARIN | US | 24th Nov 1993 |
| 198.181.162.0/24 | 256 | ARIN | US | 24th Nov 1993 |
| 198.181.164.0/24 | 256 | ARIN | US | 26th Nov 1993 |
| 198.181.165.0/24 | 256 | ARIN | US | 26th Nov 1993 |
| 198.181.169.0/24 | 256 | ARIN | US | 26th Nov 1993 |
| 198.181.170.0/23 | 512 | ARIN | US | 26th Nov 1993 |
| 198.181.172.0/24 | 256 | ARIN | US | 26th Nov 1993 |
| 198.181.173.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.174.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.175.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.176.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.177.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.179.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.180.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.181.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.185.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.186.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.187.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.188.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.189.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.190.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.191.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.192.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.193.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.194.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.195.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.196.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.197.0/24 | 256 | ARIN | US | 30th Nov 1993 |
| 198.181.198.0/24 | 256 | ARIN | US | 1st Dec 1993 |
| 198.181.206.0/24 | 256 | ARIN | US | 1st Dec 1993 |
| 198.181.207.0/24 | 256 | ARIN | US | 1st Dec 1993 |
| 198.181.208.0/22 | 1k | ARIN | US | 1st Dec 1993 |
| 198.181.212.0/23 | 512 | ARIN | US | 1st Dec 1993 |
| 198.181.215.0/24 | 256 | ARIN | US | 2nd Dec 1993 |
| 198.181.216.0/24 | 256 | ARIN | US | 2nd Dec 1993 |
| 198.181.217.0/24 | 256 | ARIN | US | 2nd Dec 1993 |
| 198.181.221.0/24 | 256 | ARIN | US | 2nd Dec 1993 |
| 198.181.222.0/24 | 256 | ARIN | US | 2nd Dec 1993 |
| 198.181.227.0/24 | 256 | ARIN | US | 2nd Dec 1993 |
| 198.181.228.0/24 | 256 | ARIN | US | 2nd Dec 1993 |
| 198.181.232.0/24 | 256 | ARIN | US | 2nd Dec 1993 |