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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
Browse by country
Countries with the most unannounced blocks, largest first.
Unannounced blocks
84,968 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 137.83.78.0/24 | 256 | ARIN |  US | 16th Apr 2020 |
| 137.83.88.0/24 | 256 | ARIN | US | 28th Jan 2026 |
| 138.10.0.0/16 | 65.5k | ARIN |  CA | 6th Dec 1989 |
| 138.112.0.0/16 | 65.5k | ARIN | US | 1st May 1990 |
| 138.114.0.0/16 | 65.5k | ARIN | US | 4th May 1990 |
| 138.121.176.0/22 | 1k | LACNIC |  CL | 11th Jun 2015 |
| 138.121.68.0/22 | 1k | LACNIC |  BR | 3rd Jun 2015 |
| 138.124.154.0/23 | 512 | RIPE NCC |  CH | 1st Sept 1993 |
| 138.124.192.0/20 | 4.1k | RIPE NCC |  NL | 1st Sept 1993 |
| 138.125.0.0/16 | 65.5k | ARIN | US | 17th May 1990 |
| 138.126.0.0/16 | 65.5k | ARIN | US | 17th May 1990 |
| 138.128.128.0/23 | 512 | ARIN | US | 17th May 1990 |
| 138.129.16.0/20 | 4.1k | ARIN | US | 17th May 1990 |
| 138.129.32.0/19 | 8.2k | ARIN | US | 17th May 1990 |
| 138.129.64.0/18 | 16.4k | ARIN | US | 17th May 1990 |
| 138.16.136.0/24 | 256 | RIPE NCC |  RU | 23rd Jan 1990 |
| 138.16.144.0/21 | 2k | RIPE NCC | RU | 23rd Jan 1990 |
| 138.16.208.0/20 | 4.1k | RIPE NCC | RU | 23rd Jan 1990 |
| 138.16.236.0/22 | 1k | RIPE NCC | RU | 23rd Jan 1990 |
| 138.185.116.0/22 | 1k | LACNIC |  PE | 31st Jul 2015 |
| 138.185.228.0/22 | 1k | LACNIC | BR | 7th Jul 2015 |
| 138.193.0.0/16 | 65.5k | ARIN | US | 21st May 1990 |
| 138.196.0.0/16 | 65.5k | ARIN | US | 24th Nov 2015 |
| 138.199.64.0/20 | 4.1k | RIPE NCC |  EU | 23rd May 1990 |
| 138.204.204.0/22 | 1k | LACNIC |  MX | 10th Aug 2015 |
| 138.208.0.0/16 | 65.5k | ARIN | US | 29th May 1990 |
| 138.209.0.0/16 | 65.5k | ARIN | US | 15th Apr 1992 |
| 138.211.0.0/16 | 65.5k | APNIC |  NZ | 30th May 1990 |
| 138.214.0.0/16 | 65.5k | ARIN | CA | 31st May 1990 |
| 138.219.80.0/22 | 1k | LACNIC |  AR | 11th Aug 2015 |
| 138.228.0.0/16 | 65.5k | RIPE NCC | CH | 1st Sept 1993 |
| 138.241.0.0/16 | 65.5k | ARIN | US | 8th Jun 1990 |
| 138.243.0.0/16 | 65.5k | APNIC |  JP | 11th Jun 1990 |
| 138.252.102.0/23 | 512 | APNIC |  BD | 27th Oct 2025 |
| 138.252.116.0/23 | 512 | APNIC |  TW | 30th Oct 2025 |
| 138.252.118.0/23 | 512 | APNIC |  CN | 30th Oct 2025 |
| 138.252.122.0/23 | 512 | APNIC |  ID | 31st Oct 2025 |
| 138.252.132.0/23 | 512 | APNIC |  VN | 3rd Nov 2025 |
| 138.252.142.0/23 | 512 | APNIC | VN | 5th Nov 2025 |
| 138.252.162.0/23 | 512 | APNIC | CN | 6th Nov 2025 |
| 138.252.167.0/24 | 256 | APNIC |  PH | 10th Nov 2025 |
| 138.252.182.0/24 | 256 | APNIC |  TL | 11th Nov 2025 |
| 138.252.196.0/23 | 512 | APNIC |  HK | 13th Nov 2025 |
| 138.252.210.0/24 | 256 | APNIC | ID | 14th Nov 2025 |
| 138.252.211.0/24 | 256 | APNIC | HK | 14th Nov 2025 |
| 138.252.216.0/24 | 256 | APNIC |  AU | 17th Nov 2025 |
| 138.252.217.0/24 | 256 | APNIC | ID | 17th Nov 2025 |
| 138.252.218.0/23 | 512 | APNIC | VN | 17th Nov 2025 |
| 138.252.230.0/23 | 512 | APNIC |  IN | 18th Nov 2025 |
| 138.252.250.0/23 | 512 | APNIC | AU | 19th Nov 2025 |