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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 in United States
27,007 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.16.182.0/24 | 256 | ARIN |  US | 7th Nov 1986 |
| 192.16.203.0/24 | 256 | ARIN | US | 21st Nov 1986 |
| 192.16.64.0/21 | 2k | ARIN | US | 5th Nov 2012 |
| 192.16.72.0/24 | 256 | ARIN | US | 27th Jun 1986 |
| 192.16.74.0/24 | 256 | ARIN | US | 27th Jun 1986 |
| 192.160.0.0/24 | 256 | ARIN | US | 9th Dec 2016 |
| 192.160.1.0/24 | 256 | ARIN | US | 20th Apr 1992 |
| 192.160.101.0/24 | 256 | ARIN | US | 9th Jul 2015 |
| 192.160.104.0/24 | 256 | ARIN | US | 15th Apr 1993 |
| 192.160.105.0/24 | 256 | ARIN | US | 15th Apr 1993 |
| 192.160.107.0/24 | 256 | ARIN | US | 15th Apr 1993 |
| 192.160.11.0/24 | 256 | ARIN | US | 21st Apr 1992 |
| 192.160.12.0/24 | 256 | ARIN | US | 22nd Apr 1992 |
| 192.160.122.0/24 | 256 | ARIN | US | 20th May 1992 |
| 192.160.124.0/24 | 256 | ARIN | US | 21st May 1992 |
| 192.160.125.0/24 | 256 | ARIN | US | 21st May 1992 |
| 192.160.129.0/24 | 256 | ARIN | US | 21st May 1992 |
| 192.160.133.0/24 | 256 | ARIN | US | 21st May 1992 |
| 192.160.134.0/24 | 256 | ARIN | US | 21st May 1992 |
| 192.160.135.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.160.136.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.160.137.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.160.139.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.160.14.0/24 | 256 | ARIN | US | 2nd Jul 2026 |
| 192.160.140.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.160.141.0/24 | 256 | ARIN | US | 22nd May 1992 |
| 192.160.147.0/24 | 256 | ARIN | US | 27th May 1992 |
| 192.160.149.0/24 | 256 | ARIN | US | 27th May 1992 |
| 192.160.150.0/24 | 256 | ARIN | US | 27th May 1992 |
| 192.160.151.0/24 | 256 | ARIN | US | 27th May 1992 |
| 192.160.153.0/24 | 256 | ARIN | US | 27th May 1992 |
| 192.160.154.0/24 | 256 | ARIN | US | 27th May 1992 |
| 192.160.168.0/24 | 256 | ARIN | US | 1st Jun 1992 |
| 192.160.17.0/24 | 256 | ARIN | US | 22nd Apr 1992 |
| 192.160.173.0/24 | 256 | ARIN | US | 2nd Jun 1992 |
| 192.160.180.0/24 | 256 | ARIN | US | 2nd Jun 1992 |
| 192.160.181.0/24 | 256 | ARIN | US | 2nd Jun 1992 |
| 192.160.184.0/24 | 256 | ARIN | US | 18th Nov 2022 |
| 192.160.185.0/24 | 256 | ARIN | US | 3rd Jun 1992 |
| 192.160.186.0/24 | 256 | ARIN | US | 3rd Jun 1992 |
| 192.160.187.0/24 | 256 | ARIN | US | 3rd Jun 1992 |
| 192.160.189.0/24 | 256 | ARIN | US | 3rd Jun 1992 |
| 192.160.190.0/24 | 256 | ARIN | US | 3rd Jun 1992 |
| 192.160.191.0/24 | 256 | ARIN | US | 3rd Jun 1992 |
| 192.160.199.0/24 | 256 | ARIN | US | 9th Jun 1992 |
| 192.160.2.0/24 | 256 | ARIN | US | 21st Apr 1992 |
| 192.160.20.0/24 | 256 | ARIN | US | 22nd Apr 1992 |
| 192.160.200.0/23 | 512 | ARIN | US | 9th Jun 1992 |
| 192.160.202.0/24 | 256 | ARIN | US | 9th Jun 1992 |
| 192.160.203.0/24 | 256 | ARIN | US | 9th Jun 1992 |