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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 in United States
27,034 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 198.203.155.0/24 | 256 | ARIN |  US | 21st Apr 1994 |
| 198.203.156.0/22 | 1k | ARIN | US | 21st Apr 1994 |
| 198.203.160.0/22 | 1k | ARIN | US | 25th Apr 1994 |
| 198.203.164.0/24 | 256 | ARIN | US | 25th Apr 1994 |
| 198.203.165.0/24 | 256 | ARIN | US | 25th Apr 1994 |
| 198.203.166.0/24 | 256 | ARIN | US | 25th Apr 1994 |
| 198.203.167.0/24 | 256 | ARIN | US | 25th Apr 1994 |
| 198.203.168.0/24 | 256 | ARIN | US | 25th Apr 1994 |
| 198.203.170.0/24 | 256 | ARIN | US | 27th Apr 1994 |
| 198.203.171.0/24 | 256 | ARIN | US | 27th Apr 1994 |
| 198.203.172.0/24 | 256 | ARIN | US | 27th Apr 1994 |
| 198.203.182.0/24 | 256 | ARIN | US | 28th Apr 1994 |
| 198.203.183.0/24 | 256 | ARIN | US | 28th Apr 1994 |
| 198.203.184.0/24 | 256 | ARIN | US | 28th Apr 1994 |
| 198.203.185.0/24 | 256 | ARIN | US | 28th Apr 1994 |
| 198.203.188.0/24 | 256 | ARIN | US | 28th Apr 1994 |
| 198.203.189.0/24 | 256 | ARIN | US | 28th Apr 1994 |
| 198.203.190.0/24 | 256 | ARIN | US | 28th Apr 1994 |
| 198.203.192.0/24 | 256 | ARIN | US | 28th Apr 1994 |
| 198.203.193.0/24 | 256 | ARIN | US | 28th Apr 1994 |
| 198.203.206.0/24 | 256 | ARIN | US | 3rd May 1994 |
| 198.203.207.0/24 | 256 | ARIN | US | 3rd May 1994 |
| 198.203.208.0/22 | 1k | ARIN | US | 4th May 1994 |
| 198.203.212.0/24 | 256 | ARIN | US | 4th May 1994 |
| 198.203.214.0/24 | 256 | ARIN | US | 4th May 1994 |
| 198.203.215.0/24 | 256 | ARIN | US | 5th May 1994 |
| 198.203.216.0/24 | 256 | ARIN | US | 5th May 1994 |
| 198.203.217.0/24 | 256 | ARIN | US | 5th May 1994 |
| 198.203.218.0/24 | 256 | ARIN | US | 5th May 1994 |
| 198.203.224.0/24 | 256 | ARIN | US | 6th May 1994 |
| 198.203.225.0/24 | 256 | ARIN | US | 6th May 1994 |
| 198.203.226.0/24 | 256 | ARIN | US | 9th May 1994 |
| 198.203.227.0/24 | 256 | ARIN | US | 10th May 1994 |
| 198.203.230.0/24 | 256 | ARIN | US | 10th May 1994 |
| 198.203.231.0/24 | 256 | ARIN | US | 10th May 1994 |
| 198.203.233.0/24 | 256 | ARIN | US | 11th May 1994 |
| 198.203.234.0/24 | 256 | ARIN | US | 11th May 1994 |
| 198.203.236.0/24 | 256 | ARIN | US | 11th May 1994 |
| 198.203.24.0/23 | 512 | ARIN | US | 22nd Jun 1993 |
| 198.203.246.0/23 | 512 | ARIN | US | 11th May 1994 |
| 198.203.248.0/23 | 512 | ARIN | US | 11th May 1994 |
| 198.203.26.0/23 | 512 | ARIN | US | 28th Jan 2013 |
| 198.203.28.0/23 | 512 | ARIN | US | 10th Oct 2012 |
| 198.203.4.0/22 | 1k | ARIN | US | 24th Feb 2020 |
| 198.203.40.0/22 | 1k | ARIN | US | 12th Aug 1993 |
| 198.203.8.0/21 | 2k | ARIN | US | 22nd Jun 1993 |
| 198.204.0.0/21 | 2k | ARIN | US | 22nd Jun 1993 |
| 198.204.106.0/24 | 256 | ARIN | US | 19th May 1994 |
| 198.204.107.0/24 | 256 | ARIN | US | 19th May 1994 |
| 198.204.108.0/24 | 256 | ARIN | US | 19th May 1994 |