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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks registered through ARIN
30,430 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 155.94.80.0/20 | 4.1k | ARIN |  US | 13th Oct 2022 |
| 155.96.0.0/16 | 65.5k | ARIN | US | 13th Nov 1991 |
| 156.100.0.0/16 | 65.5k | ARIN | US | 24th Dec 1991 |
| 156.102.0.0/16 | 65.5k | ARIN | US | 24th Dec 1991 |
| 156.103.0.0/16 | 65.5k | ARIN | US | 24th Dec 1991 |
| 156.104.0.0/16 | 65.5k | ARIN | US | 24th Dec 1991 |
| 156.105.0.0/16 | 65.5k | ARIN | US | 24th Dec 1991 |
| 156.117.0.0/16 | 65.5k | ARIN | US | 8th Jan 1992 |
| 156.119.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.120.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.121.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.122.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.123.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.124.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.125.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.126.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.127.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.128.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.129.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.130.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.131.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.132.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.136.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.140.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.141.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 156.152.0.0/16 | 65.5k | ARIN | US | 17th Dec 1993 |
| 156.154.114.0/23 | 512 | ARIN | US | 18th Dec 2003 |
| 156.154.134.0/24 | 256 | ARIN | US | 18th Dec 2003 |
| 156.154.146.0/24 | 256 | ARIN | US | 18th Dec 2003 |
| 156.154.147.0/24 | 256 | ARIN | US | 18th Dec 2003 |
| 156.154.168.0/24 | 256 | ARIN | US | 18th Dec 2003 |
| 156.154.176.0/23 | 512 | ARIN | US | 18th Dec 2003 |
| 156.154.185.0/24 | 256 | ARIN | US | 18th Dec 2003 |
| 156.154.186.0/23 | 512 | ARIN | US | 18th Dec 2003 |
| 156.154.204.0/22 | 1k | ARIN | US | 18th Dec 2003 |
| 156.154.32.0/23 | 512 | ARIN | US | 18th Dec 2003 |
| 156.154.44.0/22 | 1k | ARIN | US | 18th Dec 2003 |
| 156.154.48.0/22 | 1k | ARIN | US | 18th Dec 2003 |
| 156.154.61.0/24 | 256 | ARIN | US | 18th Dec 2003 |
| 156.154.81.0/24 | 256 | ARIN | US | 18th Dec 2003 |
| 156.154.93.0/24 | 256 | ARIN | US | 18th Dec 2003 |
| 156.24.0.0/16 | 65.5k | ARIN | US | 25th Nov 1991 |
| 156.32.0.0/16 | 65.5k | ARIN | US | 3rd Dec 1991 |
| 156.36.0.0/16 | 65.5k | ARIN | US | 9th Dec 1991 |
| 156.4.0.0/15 | 131k | ARIN | US | 27th Apr 2020 |
| 156.45.192.0/19 | 8.2k | ARIN | US | 9th Dec 1991 |
| 156.45.240.0/20 | 4.1k | ARIN | US | 9th Dec 1991 |
| 156.70.0.0/23 | 512 | ARIN | US | 19th Dec 1991 |
| 156.70.100.0/22 | 1k | ARIN | US | 19th Dec 1991 |
| 156.70.104.0/22 | 1k | ARIN | US | 19th Dec 1991 |