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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,149 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 192.200.53.0/24 | 256 | ARIN |  US | 22nd Jul 1992 |
| 192.200.54.0/24 | 256 | ARIN | US | 22nd Jul 1992 |
| 192.200.55.0/24 | 256 | ARIN | US | 22nd Jul 1992 |
| 192.200.56.0/24 | 256 | ARIN | US | 22nd Jul 1992 |
| 192.200.57.0/24 | 256 | ARIN | US | 29th Dec 1992 |
| 192.200.58.0/23 | 512 | ARIN | US | 29th Dec 1992 |
| 192.200.64.0/20 | 4.1k | APNIC |  NZ | 6th Aug 1992 |
| 192.201.0.0/16 | 65.5k | ARIN | US | 24th Jul 1992 |
| 192.203.106.0/24 | 256 | ARIN |  CA | 5th Aug 1992 |
| 192.203.107.0/24 | 256 | ARIN | CA | 24th Aug 1992 |
| 192.203.108.0/23 | 512 | RIPE NCC |  FI | 21st Aug 1992 |
| 192.203.110.0/23 | 512 | ARIN | US | 26th Aug 1992 |
| 192.203.112.0/23 | 512 | ARIN | US | 26th Aug 1992 |
| 192.203.114.0/24 | 256 | ARIN | US | 26th Aug 1992 |
| 192.203.115.0/24 | 256 | ARIN | US | 26th Aug 1992 |
| 192.203.116.0/24 | 256 | ARIN | US | 26th Aug 1992 |
| 192.203.118.0/23 | 512 | ARIN | US | 26th Aug 1992 |
| 192.203.120.0/22 | 1k | ARIN | US | 26th Aug 1992 |
| 192.203.128.0/23 | 512 | ARIN | US | 26th Aug 1992 |
| 192.203.133.0/24 | 256 | ARIN | US | 27th Aug 1992 |
| 192.203.135.0/24 | 256 | ARIN | US | 27th Aug 1992 |
| 192.203.147.0/24 | 256 | ARIN | US | 14th Sept 1992 |
| 192.203.148.0/24 | 256 | ARIN | US | 14th Sept 1992 |
| 192.203.149.0/24 | 256 | ARIN | US | 14th Sept 1992 |
| 192.203.151.0/24 | 256 | ARIN | US | 6th Jul 2026 |
| 192.203.152.0/24 | 256 | ARIN | US | 15th Sept 1992 |
| 192.203.153.0/24 | 256 | ARIN | US | 16th Sept 1992 |
| 192.203.154.0/24 | 256 | APNIC | NZ | 17th Sept 1992 |
| 192.203.156.0/23 | 512 | APNIC |  IN | 1st Jan 2026 |
| 192.203.158.0/24 | 256 | LACNIC |  CL | 17th Sept 1992 |
| 192.203.159.0/24 | 256 | ARIN | US | 17th Sept 1992 |
| 192.203.160.0/24 | 256 | ARIN | US | 17th Sept 1992 |
| 192.203.161.0/24 | 256 | ARIN | US | 17th Sept 1992 |
| 192.203.162.0/24 | 256 | ARIN | US | 17th Sept 1992 |
| 192.203.163.0/24 | 256 | ARIN | US | 17th Sept 1992 |
| 192.203.165.0/24 | 256 | ARIN | US | 18th Sept 1992 |
| 192.203.166.0/24 | 256 | ARIN | US | 18th Sept 1992 |
| 192.203.167.0/24 | 256 | ARIN | US | 18th Sept 1992 |
| 192.203.168.0/24 | 256 | ARIN | US | 18th Sept 1992 |
| 192.203.169.0/24 | 256 | ARIN | US | 18th Sept 1992 |
| 192.203.170.0/24 | 256 | ARIN | US | 18th Sept 1992 |
| 192.203.171.0/24 | 256 | ARIN | US | 18th Sept 1992 |
| 192.203.172.0/24 | 256 | ARIN | US | 18th Sept 1992 |
| 192.203.173.0/24 | 256 | ARIN | US | 18th Sept 1992 |
| 192.203.174.0/24 | 256 | ARIN | US | 18th Sept 1992 |
| 192.203.176.0/24 | 256 | APNIC |  AU | 18th Sept 1992 |
| 192.203.179.0/24 | 256 | ARIN | US | 21st Sept 1992 |
| 192.203.182.0/24 | 256 | ARIN | US | 21st Sept 1992 |
| 192.203.183.0/24 | 256 | APNIC |  HK | 7th Feb 2011 |
| 192.203.184.0/23 | 512 | APNIC | HK | 7th Feb 2011 |