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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,356 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 205.210.51.0/24 | 256 | ARIN |  CA | 8th Apr 1995 |
| 205.210.54.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.55.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.56.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.57.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.58.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.59.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.60.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.61.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.62.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.63.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.70.0/24 | 256 | ARIN |  US | 1st Jul 2025 |
| 205.210.71.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.72.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.73.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.74.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.78.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.79.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.8.0/21 | 2k | ARIN | CA | 8th Apr 1995 |
| 205.210.80.0/22 | 1k | ARIN | CA | 8th Apr 1995 |
| 205.210.84.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.210.96.0/21 | 2k | ARIN | CA | 8th Apr 1995 |
| 205.211.1.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.211.129.0/24 | 256 | ARIN | CA | 8th Nov 1995 |
| 205.211.138.0/23 | 512 | ARIN | CA | 24th Oct 1995 |
| 205.211.14.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.211.146.0/24 | 256 | ARIN | CA | 15th Nov 1995 |
| 205.211.147.0/24 | 256 | ARIN | CA | 17th Nov 1995 |
| 205.211.149.0/24 | 256 | ARIN | CA | 6th Dec 1995 |
| 205.211.15.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.211.150.0/23 | 512 | ARIN | CA | 4th Jan 1996 |
| 205.211.161.0/24 | 256 | ARIN | CA | 16th Jan 1996 |
| 205.211.170.0/24 | 256 | ARIN | CA | 13th Feb 1996 |
| 205.211.171.0/24 | 256 | ARIN | CA | 2nd Apr 1996 |
| 205.211.172.0/24 | 256 | ARIN | CA | 22nd Feb 1996 |
| 205.211.173.0/24 | 256 | ARIN | CA | 29th Feb 1996 |
| 205.211.174.0/24 | 256 | ARIN | CA | 29th Feb 1996 |
| 205.211.175.0/24 | 256 | ARIN | CA | 7th Mar 1996 |
| 205.211.176.0/23 | 512 | ARIN | CA | 4th Mar 1996 |
| 205.211.179.0/24 | 256 | ARIN | CA | 12th Mar 1996 |
| 205.211.3.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.211.79.0/24 | 256 | ARIN | CA | 29th Aug 1995 |
| 205.211.80.0/24 | 256 | ARIN | CA | 8th Apr 1995 |
| 205.211.81.0/24 | 256 | ARIN | CA | 14th Oct 1995 |
| 205.211.82.0/24 | 256 | ARIN | CA | 23rd Oct 1995 |
| 205.211.84.0/22 | 1k | ARIN | CA | 8th Apr 1995 |
| 205.214.128.0/19 | 8.2k | ARIN | US | 18th Apr 1995 |
| 205.214.96.0/19 | 8.2k | ARIN | US | 18th Apr 1995 |
| 205.220.218.0/24 | 256 | ARIN | US | 20th Jul 2018 |
| 205.220.220.0/22 | 1k | ARIN | US | 25th Sept 2018 |