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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,392 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 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 |
| 205.175.248.0/23 | 512 | ARIN | US | 12th Nov 1996 |
| 205.175.251.0/24 | 256 | ARIN | US | 12th Nov 1996 |
| 205.175.252.0/22 | 1k | ARIN | US | 12th Nov 1996 |
| 205.175.32.0/19 | 8.2k | ARIN | US | 23rd Mar 1995 |
| 205.175.64.0/19 | 8.2k | ARIN | US | 3rd Apr 1995 |
| 205.178.148.0/24 | 256 | ARIN |  CA | 9th Apr 2021 |
| 205.178.150.0/23 | 512 | ARIN | US | 9th Apr 2021 |
| 205.178.171.0/24 | 256 | ARIN | US | 12th Apr 2021 |
| 205.178.172.0/22 | 1k | ARIN | US | 8th Mar 2021 |
| 205.178.176.0/24 | 256 | RIPE NCC |  GB | 30th Mar 2021 |
| 205.184.0.0/19 | 8.2k | ARIN | US | 19th Jul 2000 |
| 205.184.32.0/20 | 4.1k | ARIN | US | 19th Jul 2000 |
| 205.185.224.0/20 | 4.1k | ARIN | US | 10th Aug 2009 |
| 205.187.128.0/19 | 8.2k | ARIN | US | 25th Nov 2024 |
| 205.187.176.0/20 | 4.1k | ARIN | US | 21st Mar 1995 |
| 205.187.192.0/18 | 16.4k | ARIN | US | 21st Mar 1995 |
| 205.189.0.0/24 | 256 | ARIN | US | 2nd Feb 2012 |
| 205.189.100.0/24 | 256 | ARIN | CA | 22nd Mar 1995 |
| 205.189.101.0/24 | 256 | ARIN | CA | 22nd Mar 1995 |
| 205.189.104.0/23 | 512 | ARIN | CA | 22nd Mar 1995 |
| 205.189.106.0/23 | 512 | ARIN | CA | 22nd Mar 1995 |
| 205.189.108.0/24 | 256 | ARIN | CA | 22nd Mar 1995 |