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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 in United States
26,315 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 199.231.100.0/22 | 1k | ARIN |  US | 5th Jul 2012 |
| 199.231.148.0/23 | 512 | ARIN | US | 12th Mar 1996 |
| 199.231.150.0/24 | 256 | ARIN | US | 12th Mar 1996 |
| 199.231.151.0/24 | 256 | ARIN | US | 1st May 2012 |
| 199.231.234.0/24 | 256 | ARIN | US | 15th Oct 2025 |
| 199.231.6.0/23 | 512 | ARIN | US | 30th Apr 2012 |
| 199.231.8.0/21 | 2k | ARIN | US | 13th Apr 1994 |
| 199.233.0.0/21 | 2k | ARIN | US | 20th Apr 1994 |
| 199.233.100.0/24 | 256 | ARIN | US | 28th Feb 1995 |
| 199.233.103.0/24 | 256 | ARIN | US | 28th Feb 1995 |
| 199.233.106.0/24 | 256 | ARIN | US | 28th Feb 1995 |
| 199.233.107.0/24 | 256 | ARIN | US | 28th Feb 1995 |
| 199.233.109.0/24 | 256 | ARIN | US | 28th Feb 1995 |
| 199.233.115.0/24 | 256 | ARIN | US | 28th Feb 1995 |
| 199.233.117.0/24 | 256 | ARIN | US | 28th Feb 1995 |
| 199.233.12.0/23 | 512 | ARIN | US | 18th Apr 1994 |
| 199.233.120.0/24 | 256 | ARIN | US | 1st Mar 1995 |
| 199.233.121.0/24 | 256 | ARIN | US | 1st Mar 1995 |
| 199.233.122.0/24 | 256 | ARIN | US | 1st Mar 1995 |
| 199.233.123.0/24 | 256 | ARIN | US | 1st Mar 1995 |
| 199.233.124.0/24 | 256 | ARIN | US | 1st Mar 1995 |
| 199.233.126.0/24 | 256 | ARIN | US | 2nd Mar 1995 |
| 199.233.127.0/24 | 256 | ARIN | US | 2nd Mar 1995 |
| 199.233.128.0/24 | 256 | ARIN | US | 2nd Mar 1995 |
| 199.233.130.0/24 | 256 | ARIN | US | 3rd Mar 1995 |
| 199.233.131.0/24 | 256 | ARIN | US | 3rd Mar 1995 |
| 199.233.133.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.134.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.135.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.136.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.137.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.138.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.139.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.140.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.141.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.143.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.145.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.146.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.147.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.148.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.149.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.150.0/24 | 256 | ARIN | US | 8th Mar 1995 |
| 199.233.151.0/24 | 256 | ARIN | US | 9th Mar 1995 |
| 199.233.152.0/24 | 256 | ARIN | US | 9th Mar 1995 |
| 199.233.153.0/24 | 256 | ARIN | US | 20th Mar 1995 |
| 199.233.156.0/24 | 256 | ARIN | US | 20th Mar 1995 |
| 199.233.158.0/24 | 256 | ARIN | US | 20th Mar 1995 |
| 199.233.159.0/24 | 256 | ARIN | US | 20th Mar 1995 |
| 199.233.160.0/24 | 256 | ARIN | US | 20th Mar 1995 |
| 199.233.161.0/24 | 256 | ARIN | US | 20th Mar 1995 |