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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
85,578 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 203.18.110.0/24 | 256 | APNIC |  CN | 14th Apr 2011 |
| 203.18.129.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.131.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.132.0/23 | 512 | APNIC | CN | 14th Apr 2011 |
| 203.18.14.0/23 | 512 | APNIC |  AU | 16th Apr 2007 |
| 203.18.144.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.153.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.154.0/24 | 256 | APNIC | AU | 15th Aug 1995 |
| 203.18.155.0/24 | 256 | APNIC | AU | 16th Aug 1995 |
| 203.18.156.0/23 | 512 | APNIC |  TW | 31st Jul 2025 |
| 203.18.160.0/24 | 256 | APNIC | AU | 16th Aug 1995 |
| 203.18.164.0/22 | 1k | APNIC | AU | 16th Aug 1995 |
| 203.18.186.0/23 | 512 | APNIC | AU | 16th Aug 1995 |
| 203.18.188.0/22 | 1k | APNIC | AU | 16th Apr 2010 |
| 203.18.19.0/24 | 256 | APNIC | AU | 2nd Aug 1995 |
| 203.18.196.0/24 | 256 | APNIC | AU | 17th Aug 1995 |
| 203.18.199.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.2.0/23 | 512 | APNIC | CN | 14th Apr 2011 |
| 203.18.204.0/22 | 1k | APNIC | AU | 17th Aug 1995 |
| 203.18.208.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.209.0/24 | 256 | APNIC | AU | 17th Aug 1995 |
| 203.18.211.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.215.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.22.0/24 | 256 | APNIC | AU | 2nd Aug 1995 |
| 203.18.224.0/22 | 1k | APNIC | AU | 18th Aug 1995 |
| 203.18.231.0/24 | 256 | APNIC | AU | 18th Aug 1995 |
| 203.18.236.0/22 | 1k | APNIC | AU | 18th Aug 1995 |
| 203.18.244.0/24 | 256 | APNIC | AU | 18th Aug 1995 |
| 203.18.28.0/24 | 256 | APNIC | AU | 2nd Aug 1995 |
| 203.18.31.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.32.0/24 | 256 | APNIC | AU | 2nd Aug 1995 |
| 203.18.37.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.4.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.48.0/23 | 512 | APNIC | CN | 14th Apr 2011 |
| 203.18.52.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.58.0/24 | 256 | APNIC | AU | 4th Aug 1995 |
| 203.18.64.0/21 | 2k | APNIC | AU | 4th Aug 1995 |
| 203.18.7.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.72.0/22 | 1k | APNIC | CN | 14th Apr 2011 |
| 203.18.76.0/23 | 512 | APNIC | AU | 4th Aug 1995 |
| 203.18.80.0/23 | 512 | APNIC | CN | 14th Apr 2011 |
| 203.18.87.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.184.64.0/20 | 4.1k | APNIC |  US | 6th Mar 2001 |
| 203.184.80.0/20 | 4.1k | APNIC | CN | 28th Apr 2006 |
| 203.185.189.0/24 | 256 | APNIC | CN | 9th Jun 2016 |
| 203.188.192.0/20 | 4.1k | APNIC | TW | 1st Dec 2005 |
| 203.189.112.0/22 | 1k | APNIC | CN | 14th Apr 2011 |
| 203.189.25.0/24 | 256 | APNIC | AU | 1st May 2008 |
| 203.19.0.0/24 | 256 | APNIC | AU | 27th Nov 2006 |
| 203.19.1.0/24 | 256 | APNIC | CN | 9th Jun 2016 |