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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
84,968 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 142.8.0.0/16 | 65.5k | ARIN |  CA | 30th Nov 1990 |
| 142.88.0.0/16 | 65.5k | ARIN |  US | 6th Jun 1994 |
| 142.95.0.0/16 | 65.5k | ARIN | CA | 3rd Jan 1992 |
| 142.96.0.0/16 | 65.5k | ARIN | CA | 3rd Jan 1992 |
| 142.97.0.0/16 | 65.5k | ARIN | CA | 26th Mar 1990 |
| 142.99.0.0/20 | 4.1k | ARIN | CA | 7th Jan 1992 |
| 142.99.104.0/23 | 512 | ARIN | CA | 7th Jan 1992 |
| 142.99.112.0/20 | 4.1k | ARIN | CA | 7th Jan 1992 |
| 142.99.16.0/22 | 1k | ARIN | CA | 7th Jan 1992 |
| 142.99.24.0/21 | 2k | RIPE NCC | CA | 7th Jan 1992 |
| 142.99.32.0/19 | 8.2k | ARIN | CA | 7th Jan 1992 |
| 142.99.64.0/19 | 8.2k | ARIN | CA | 7th Jan 1992 |
| 143.122.0.0/16 | 65.5k | ARIN | US | 19th Sept 1990 |
| 143.131.128.0/19 | 8.2k | ARIN | US | 19th Sept 1990 |
| 143.131.16.0/20 | 4.1k | ARIN | US | 19th Sept 1990 |
| 143.131.160.0/19 | 8.2k | ARIN | US | 29th Dec 2022 |
| 143.131.32.0/19 | 8.2k | ARIN | US | 19th Sept 1990 |
| 143.131.64.0/18 | 16.4k | ARIN | US | 19th Sept 1990 |
| 143.137.24.0/22 | 1k | LACNIC |  NI | 15th Sept 2015 |
| 143.162.0.0/16 | 65.5k | ARIN | US | 26th Sept 1990 |
| 143.173.0.0/16 | 65.5k | ARIN | US | 30th Jun 1990 |
| 143.174.128.0/18 | 16.4k | APNIC |  AU | 1st Oct 1990 |
| 143.174.224.0/19 | 8.2k | APNIC | AU | 1st Oct 1990 |
| 143.181.0.0/16 | 65.5k | ARIN | US | 1st Oct 1990 |
| 143.182.0.0/16 | 65.5k | ARIN | US | 1st Oct 1990 |
| 143.183.0.0/16 | 65.5k | ARIN | US | 1st Oct 1990 |
| 143.184.0.0/16 | 65.5k | ARIN | US | 1st Oct 1990 |
| 143.185.0.0/16 | 65.5k | ARIN | US | 1st Oct 1990 |
| 143.190.0.0/16 | 65.5k | ARIN | US | 1st Oct 1990 |
| 143.192.112.0/20 | 4.1k | APNIC |  SG | 1st Oct 1990 |
| 143.192.64.0/19 | 8.2k | ARIN | US | 1st Oct 1990 |
| 143.193.0.0/16 | 65.5k | ARIN | US | 30th Jun 1990 |
| 143.201.0.0/16 | 65.5k | APNIC |  JP | 10th Feb 2011 |
| 143.202.20.0/22 | 1k | LACNIC |  AR | 29th Sept 2015 |
| 143.217.0.0/16 | 65.5k | RIPE NCC |  SE | 30th Jun 1990 |
| 143.219.0.0/16 | 65.5k | ARIN | US | 30th Jun 1990 |
| 143.222.0.0/16 | 65.5k | ARIN | US | 30th Jun 1990 |
| 143.223.136.0/24 | 256 | ARIN | US | 30th Jun 1990 |
| 143.223.140.0/23 | 512 | ARIN | US | 30th Jun 1990 |
| 143.223.16.0/23 | 512 | ARIN | US | 18th Feb 2026 |
| 143.223.160.0/24 | 256 | ARIN | US | 20th Feb 2026 |
| 143.223.161.0/24 | 256 | ARIN | US | 30th Jun 1990 |
| 143.223.164.0/22 | 1k | ARIN | US | 30th Jun 1990 |
| 143.223.173.0/24 | 256 | ARIN | US | 30th Jun 1990 |
| 143.223.175.0/24 | 256 | ARIN | US | 30th Jun 1990 |
| 143.223.177.0/24 | 256 | RIPE NCC |  NO | 30th Jun 1990 |
| 143.223.180.0/22 | 1k | ARIN | US | 30th Jun 1990 |
| 143.223.20.0/22 | 1k | ARIN | US | 30th Jun 1990 |
| 143.237.0.0/16 | 65.5k | RIPE NCC | SE | 23rd Oct 1990 |
| 143.242.0.0/16 | 65.5k | ARIN | US | 23rd Oct 1990 |