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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,001 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 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 |
| 151.105.0.0/16 | 65.5k | ARIN |  FI | 30th May 1991 |
| 151.108.0.0/16 | 65.5k | ARIN |  US | 30th May 1991 |
| 151.109.0.0/16 | 65.5k | ARIN | US | 16th May 1991 |
| 151.116.0.0/15 | 131k | ARIN | US | 11th Jun 1991 |
| 151.118.0.0/16 | 65.5k | ARIN | US | 11th Jun 1991 |
| 151.119.0.0/16 | 65.5k | ARIN | US | 11th Jun 1991 |
| 151.123.192.0/19 | 8.2k | RIPE NCC | US | 17th Jun 1991 |
| 151.126.0.0/16 | 65.5k | ARIN | US | 17th Jun 1991 |
| 151.128.0.0/16 | 65.5k | ARIN | US | 17th Jun 1991 |
| 151.146.0.0/16 | 65.5k | ARIN |  SG | 26th Feb 1991 |
| 151.148.16.0/20 | 4.1k | ARIN | US | 19th Sept 2022 |
| 151.148.8.0/21 | 2k | ARIN | US | 19th Sept 2022 |
| 151.158.102.0/23 | 512 | APNIC |  VN | 29th Jan 2026 |
| 151.158.104.0/23 | 512 | APNIC |  IN | 29th Jan 2026 |
| 151.158.122.0/23 | 512 | APNIC |  CN | 2nd Feb 2026 |
| 151.158.14.0/23 | 512 | APNIC | CN | 14th Jan 2026 |
| 151.158.140.0/23 | 512 | APNIC | IN | 4th Feb 2026 |
| 151.158.148.0/23 | 512 | APNIC | IN | 6th Feb 2026 |
| 151.158.154.0/23 | 512 | APNIC |  BD | 9th Feb 2026 |
| 151.158.156.0/23 | 512 | APNIC | IN | 9th Feb 2026 |
| 151.158.160.0/23 | 512 | APNIC |  TW | 10th Feb 2026 |
| 151.158.174.0/23 | 512 | APNIC |  PK | 13th Feb 2026 |
| 151.158.183.0/24 | 256 | APNIC |  ID | 16th Feb 2026 |
| 151.158.186.0/24 | 256 | APNIC | ID | 16th Feb 2026 |
| 151.158.192.0/22 | 1k | APNIC | IN | 17th Feb 2026 |
| 151.158.20.0/23 | 512 | APNIC |  TL | 15th Jan 2026 |
| 151.158.202.0/24 | 256 | APNIC | ID | 19th Feb 2026 |
| 151.158.209.0/24 | 256 | APNIC |  MV | 23rd Feb 2026 |
| 151.158.222.0/23 | 512 | APNIC | JP | 24th Feb 2026 |
| 151.158.228.0/23 | 512 | APNIC | IN | 24th Feb 2026 |
| 151.158.238.0/24 | 256 | APNIC |  MM | 26th Feb 2026 |
| 151.158.240.0/23 | 512 | APNIC | ID | 27th Feb 2026 |
| 151.158.251.0/24 | 256 | APNIC |  PH | 4th Mar 2026 |
| 151.158.38.0/23 | 512 | APNIC |  AU | 16th Jan 2026 |
| 151.158.40.0/23 | 512 | APNIC | AU | 16th Jan 2026 |
| 151.158.68.0/23 | 512 | APNIC | AU | 23rd Jan 2026 |
| 151.158.74.0/23 | 512 | APNIC | ID | 23rd Jan 2026 |
| 151.158.78.0/23 | 512 | APNIC | CN | 23rd Jan 2026 |
| 151.158.80.0/23 | 512 | APNIC | CN | 23rd Jan 2026 |
| 151.158.82.0/23 | 512 | APNIC | ID | 26th Jan 2026 |
| 151.158.94.0/23 | 512 | APNIC | VN | 28th Jan 2026 |
| 151.167.0.0/16 | 65.5k | ARIN | US | 7th Aug 1991 |
| 151.168.0.0/16 | 65.5k | ARIN | US | 7th Aug 1991 |
| 151.171.0.0/16 | 65.5k | ARIN | US | 5th Sept 1991 |
| 151.174.0.0/16 | 65.5k | ARIN | US | 5th Sept 1991 |