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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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.
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Countries with the most unannounced blocks, largest first.
Unannounced blocks in United States
27,021 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 204.77.141.0/24 | 256 | ARIN |  US | 19th May 1995 |
| 204.77.142.0/24 | 256 | ARIN | US | 19th May 1995 |
| 204.77.143.0/24 | 256 | ARIN | US | 14th Feb 1995 |
| 204.77.144.0/24 | 256 | ARIN | US | 14th Feb 1995 |
| 204.77.146.0/24 | 256 | ARIN | US | 25th Jul 1996 |
| 204.77.147.0/24 | 256 | ARIN | US | 1st Feb 1995 |
| 204.77.150.0/24 | 256 | ARIN | US | 22nd Aug 1995 |
| 204.77.152.0/24 | 256 | ARIN | US | 1st Sept 1995 |
| 204.77.154.0/24 | 256 | ARIN | US | 28th Apr 1996 |
| 204.77.155.0/24 | 256 | ARIN | US | 25th Jul 1996 |
| 204.77.156.0/24 | 256 | ARIN | US | 28th Apr 1996 |
| 204.77.157.0/24 | 256 | ARIN | US | 27th Jun 1996 |
| 204.77.158.0/24 | 256 | ARIN | US | 27th Jun 1996 |
| 204.77.159.0/24 | 256 | ARIN | US | 28th Apr 1996 |
| 204.77.16.0/21 | 2k | ARIN | US | 28th Jun 1994 |
| 204.77.160.0/24 | 256 | ARIN | US | 28th Apr 1996 |
| 204.77.170.0/24 | 256 | ARIN | US | 19th May 1996 |
| 204.77.172.0/24 | 256 | ARIN | US | 19th May 1996 |
| 204.77.173.0/24 | 256 | ARIN | US | 19th May 1996 |
| 204.77.174.0/24 | 256 | ARIN | US | 8th Jun 1998 |
| 204.77.175.0/24 | 256 | ARIN | US | 19th May 1996 |
| 204.77.176.0/24 | 256 | ARIN | US | 21st May 1996 |
| 204.77.177.0/24 | 256 | ARIN | US | 26th Jun 1996 |
| 204.77.178.0/24 | 256 | ARIN | US | 25th Jul 1996 |
| 204.77.179.0/24 | 256 | ARIN | US | 26th Jun 1996 |
| 204.77.180.0/24 | 256 | ARIN | US | 21st May 1996 |
| 204.77.181.0/24 | 256 | ARIN | US | 21st May 1996 |
| 204.77.183.0/24 | 256 | ARIN | US | 21st May 1996 |
| 204.77.184.0/24 | 256 | ARIN | US | 25th Jul 1996 |
| 204.77.185.0/24 | 256 | ARIN | US | 25th Jul 1996 |
| 204.77.186.0/23 | 512 | ARIN | US | 25th Jun 1996 |
| 204.77.188.0/24 | 256 | ARIN | US | 21st May 1996 |
| 204.77.190.0/24 | 256 | ARIN | US | 21st May 1996 |
| 204.77.191.0/24 | 256 | ARIN | US | 25th Jun 1996 |
| 204.77.192.0/24 | 256 | ARIN | US | 23rd Jun 1996 |
| 204.77.193.0/24 | 256 | ARIN | US | 3rd Oct 2011 |
| 204.77.194.0/24 | 256 | ARIN | US | 17th Jul 2025 |
| 204.77.196.0/24 | 256 | ARIN | US | 3rd Oct 2011 |
| 204.77.197.0/24 | 256 | ARIN | US | 12th Jun 1998 |
| 204.77.198.0/24 | 256 | ARIN | US | 25th Jun 1996 |
| 204.77.199.0/24 | 256 | ARIN | US | 4th Oct 2011 |
| 204.77.200.0/24 | 256 | ARIN | US | 25th Jun 1996 |
| 204.77.201.0/24 | 256 | ARIN | US | 23rd Jun 1996 |
| 204.77.202.0/23 | 512 | ARIN | US | 12th Jun 1998 |
| 204.77.204.0/23 | 512 | ARIN | US | 12th Jun 1998 |
| 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 |