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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
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Countries with the most unannounced blocks, largest first.
Unannounced blocks in United States
26,941 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 204.77.207.0/24 | 256 | ARIN |  US | 25th Jun 1996 |
| 204.77.208.0/22 | 1k | ARIN | US | 25th Jun 1996 |
| 204.77.212.0/23 | 512 | ARIN | US | 19th Apr 2011 |
| 204.77.214.0/24 | 256 | ARIN | US | 6th Oct 2011 |
| 204.77.215.0/24 | 256 | ARIN | US | 25th Jun 1996 |
| 204.77.218.0/23 | 512 | ARIN | US | 12th May 1996 |
| 204.77.220.0/23 | 512 | ARIN | US | 12th May 1996 |
| 204.77.26.0/24 | 256 | ARIN | US | 28th Jun 1994 |
| 204.77.28.0/22 | 1k | ARIN | US | 30th Dec 2008 |
| 204.78.16.0/20 | 4.1k | ARIN | US | 28th Jun 1994 |
| 204.78.32.0/19 | 8.2k | ARIN | US | 11th Aug 1994 |
| 204.79.143.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.144.0/23 | 512 | ARIN | US | 14th Dec 1994 |
| 204.79.150.0/23 | 512 | ARIN | US | 14th Dec 1994 |
| 204.79.152.0/22 | 1k | ARIN | US | 14th Dec 1994 |
| 204.79.156.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.160.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.164.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.172.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.174.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.175.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.176.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.181.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.184.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.185.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.186.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.188.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.189.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.190.0/24 | 256 | ARIN | US | 14th Dec 1994 |
| 204.79.201.0/24 | 256 | ARIN | US | 19th Dec 1994 |
| 204.79.202.0/24 | 256 | ARIN | US | 19th Dec 1994 |
| 204.79.203.0/24 | 256 | ARIN | US | 19th Dec 1994 |
| 204.79.205.0/24 | 256 | ARIN | US | 19th Dec 1994 |
| 204.79.206.0/24 | 256 | ARIN | US | 19th Dec 1994 |
| 204.79.212.0/24 | 256 | ARIN | US | 19th Dec 1994 |
| 204.79.220.0/22 | 1k | ARIN | US | 19th Dec 1994 |
| 204.79.237.0/24 | 256 | ARIN | US | 19th Dec 1994 |
| 204.79.238.0/23 | 512 | ARIN | US | 19th Dec 1994 |
| 204.79.243.0/24 | 256 | ARIN | US | 19th Dec 1994 |
| 204.8.200.0/22 | 1k | ARIN | US | 12th Aug 2004 |
| 204.8.208.0/21 | 2k | ARIN | US | 18th Aug 2004 |
| 204.80.129.0/24 | 256 | ARIN | US | 12th Dec 1994 |
| 204.80.131.0/24 | 256 | ARIN | US | 15th Dec 1994 |
| 204.80.133.0/24 | 256 | ARIN | US | 15th Dec 1994 |
| 204.80.134.0/24 | 256 | ARIN | US | 10th Jan 1995 |
| 204.80.135.0/24 | 256 | ARIN | US | 10th Jan 1995 |
| 204.80.137.0/24 | 256 | ARIN | US | 10th Jan 1995 |
| 204.80.138.0/24 | 256 | ARIN | US | 10th Jan 1995 |
| 204.80.139.0/24 | 256 | ARIN | US | 10th Jan 1995 |
| 204.80.140.0/24 | 256 | ARIN | US | 10th Jan 1995 |