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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 Japan
1,447 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 150.36.0.0/16 | 65.5k | APNIC |  JP | 31st Mar 1997 |
| 150.4.0.0/16 | 65.5k | APNIC | JP | 31st Mar 1997 |
| 150.40.0.0/18 | 16.4k | APNIC | JP | 6th Apr 1995 |
| 150.40.64.0/21 | 2k | APNIC | JP | 6th Apr 1995 |
| 150.44.0.0/16 | 65.5k | APNIC | JP | 31st Mar 1997 |
| 150.45.0.0/16 | 65.5k | APNIC | JP | 23rd Jun 1992 |
| 150.48.192.0/18 | 16.4k | APNIC | JP | 4th Mar 1993 |
| 150.50.0.0/16 | 65.5k | APNIC | JP | 31st Mar 1997 |
| 150.51.0.0/16 | 65.5k | APNIC | JP | 4th Mar 1993 |
| 150.53.0.0/16 | 65.5k | APNIC | JP | 31st Mar 1997 |
| 150.58.0.0/16 | 65.5k | APNIC | JP | 31st Mar 1997 |
| 150.6.0.0/16 | 65.5k | APNIC | JP | 31st Mar 1997 |
| 150.62.0.0/16 | 65.5k | APNIC | JP | 31st Mar 1997 |
| 150.64.0.0/16 | 65.5k | APNIC | JP | 2nd Sept 1992 |
| 150.68.0.0/16 | 65.5k | APNIC | JP | 31st Mar 1997 |
| 150.72.0.0/14 | 262k | APNIC | JP | 3rd Nov 1992 |
| 150.76.0.0/14 | 262k | APNIC | JP | 23rd Mar 1993 |
| 150.8.0.0/16 | 65.5k | APNIC | JP | 31st Mar 1997 |
| 150.80.0.0/16 | 65.5k | APNIC | JP | 1st Apr 1992 |
| 150.81.0.0/16 | 65.5k | APNIC | JP | 31st Mar 1997 |
| 150.85.0.0/16 | 65.5k | APNIC | JP | 26th Apr 1994 |
| 150.88.0.0/16 | 65.5k | APNIC | JP | 10th Feb 1992 |
| 150.92.0.0/16 | 65.5k | APNIC | JP | 22nd May 1996 |
| 150.94.0.0/16 | 65.5k | APNIC | JP | 31st Mar 1997 |
| 150.95.0.0/23 | 512 | APNIC | JP | 31st Mar 1997 |
| 150.95.2.0/23 | 512 | APNIC | JP | 31st Mar 1997 |
| 150.95.4.0/22 | 1k | APNIC | JP | 31st Mar 1997 |
| 150.98.0.0/16 | 65.5k | APNIC | JP | 31st Mar 1997 |
| 151.158.222.0/23 | 512 | APNIC | JP | 24th Feb 2026 |
| 153.120.222.0/23 | 512 | APNIC | JP | 2nd Mar 2011 |
| 153.123.128.0/17 | 32.8k | APNIC | JP | 2nd Mar 2011 |
| 153.123.32.0/19 | 8.2k | APNIC | JP | 2nd Mar 2011 |
| 153.123.64.0/18 | 16.4k | APNIC | JP | 2nd Mar 2011 |
| 153.124.0.0/17 | 32.8k | APNIC | JP | 12th Mar 2011 |
| 153.124.240.0/20 | 4.1k | APNIC | JP | 12th Mar 2011 |
| 153.125.240.0/20 | 4.1k | APNIC | JP | 2nd Mar 2011 |
| 153.79.80.0/20 | 4.1k | APNIC | JP | 23rd Sept 1991 |
| 154.34.0.0/18 | 16.4k | APNIC | JP | 13th May 1996 |
| 155.160.0.0/16 | 65.5k | APNIC | JP | 14th Sept 1993 |
| 157.101.0.0/18 | 16.4k | APNIC | JP | 8th Feb 1992 |
| 157.104.0.0/16 | 65.5k | APNIC | JP | 8th Feb 1992 |
| 157.106.0.0/16 | 65.5k | APNIC | JP | 8th Feb 1992 |
| 157.108.0.0/16 | 65.5k | APNIC | JP | 8th Feb 1992 |
| 157.11.0.0/16 | 65.5k | APNIC | JP | 13th Apr 1993 |
| 157.112.128.0/20 | 4.1k | APNIC | JP | 8th Feb 1992 |
| 157.112.96.0/23 | 512 | APNIC | JP | 8th Feb 1992 |
| 157.112.98.0/24 | 256 | APNIC | JP | 8th Feb 1992 |
| 157.115.0.0/16 | 65.5k | APNIC | JP | 8th Feb 1992 |
| 157.116.0.0/16 | 65.5k | APNIC | JP | 8th Feb 1992 |
| 157.117.0.0/16 | 65.5k | APNIC | JP | 8th Feb 1992 |