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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,300 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 205.172.148.0/22 | 1k | ARIN |  US | 18th Apr 1995 |
| 205.172.152.0/22 | 1k | ARIN | US | 18th Apr 1995 |
| 205.172.180.0/22 | 1k | ARIN | US | 27th Apr 1995 |
| 205.172.188.0/22 | 1k | ARIN | US | 27th Apr 1995 |
| 205.172.196.0/22 | 1k | ARIN | US | 28th Apr 1995 |
| 205.172.200.0/22 | 1k | ARIN | US | 28th Apr 1995 |
| 205.172.204.0/22 | 1k | ARIN | US | 1st May 1995 |
| 205.172.212.0/22 | 1k | ARIN | US | 1st May 1995 |
| 205.172.216.0/22 | 1k | ARIN | US | 2nd May 1995 |
| 205.172.220.0/22 | 1k | ARIN | US | 2nd May 1995 |
| 205.172.224.0/22 | 1k | ARIN | US | 5th May 1995 |
| 205.172.244.0/22 | 1k | ARIN | US | 16th May 1995 |
| 205.172.248.0/22 | 1k | ARIN | US | 16th May 1995 |
| 205.172.252.0/22 | 1k | ARIN | US | 17th May 1995 |
| 205.172.28.0/22 | 1k | ARIN | US | 24th Mar 1995 |
| 205.172.32.0/22 | 1k | ARIN | US | 27th Mar 1995 |
| 205.172.36.0/22 | 1k | ARIN | US | 28th Mar 1995 |
| 205.172.4.0/22 | 1k | ARIN | US | 21st Mar 1995 |
| 205.172.40.0/23 | 512 | ARIN | US | 30th Mar 1995 |
| 205.172.42.0/24 | 256 | ARIN | US | 30th Mar 1995 |
| 205.172.60.0/22 | 1k | ARIN | US | 31st Mar 1995 |
| 205.172.64.0/22 | 1k | ARIN | US | 31st Mar 1995 |
| 205.172.8.0/22 | 1k | ARIN | US | 21st Mar 1995 |
| 205.173.120.0/22 | 1k | ARIN | US | 3rd Apr 1995 |
| 205.173.124.0/24 | 256 | ARIN | US | 3rd Apr 1995 |
| 205.173.128.0/21 | 2k | ARIN | US | 5th Apr 1995 |
| 205.173.136.0/21 | 2k | ARIN | US | 5th Apr 1995 |
| 205.173.16.0/21 | 2k | ARIN | US | 6th Apr 2026 |
| 205.173.184.0/21 | 2k | ARIN | US | 20th Apr 1995 |
| 205.173.192.0/21 | 2k | ARIN | US | 20th Apr 1995 |
| 205.173.48.0/21 | 2k | ARIN | US | 23rd Mar 1995 |
| 205.173.64.0/22 | 1k | ARIN | US | 27th Mar 1995 |
| 205.173.68.0/23 | 512 | ARIN | US | 27th Mar 1995 |
| 205.173.70.0/24 | 256 | ARIN | US | 27th Mar 1995 |
| 205.173.72.0/22 | 1k | ARIN | US | 27th Mar 1995 |
| 205.173.76.0/24 | 256 | ARIN | US | 27th Mar 1995 |
| 205.173.80.0/21 | 2k | ARIN | US | 29th Mar 1995 |
| 205.174.192.0/20 | 4.1k | ARIN | US | 5th Apr 1995 |
| 205.174.224.0/20 | 4.1k | ARIN | US | 22nd Jun 2011 |
| 205.174.64.0/20 | 4.1k | ARIN | US | 20th Mar 1995 |
| 205.175.0.0/19 | 8.2k | ARIN | US | 20th Mar 1995 |
| 205.175.160.0/19 | 8.2k | ARIN | US | 11th May 1995 |
| 205.175.192.0/22 | 1k | ARIN | US | 12th Nov 1996 |
| 205.175.196.0/24 | 256 | ARIN | US | 12th Nov 1996 |
| 205.175.208.0/24 | 256 | ARIN | US | 3rd Dec 1999 |
| 205.175.224.0/24 | 256 | ARIN | US | 3rd Dec 1999 |
| 205.175.230.0/23 | 512 | ARIN | US | 12th Nov 1996 |
| 205.175.232.0/22 | 1k | ARIN | US | 12th Nov 1996 |
| 205.175.236.0/23 | 512 | ARIN | US | 12th Nov 1996 |
| 205.175.247.0/24 | 256 | ARIN | US | 12th Nov 1996 |