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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 203.17.28.0/24 | 256 | APNIC |  CN | 14th Apr 2011 |
| 203.17.39.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.17.52.0/24 | 256 | APNIC |  JP | 11th Jul 1995 |
| 203.17.56.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.17.72.0/24 | 256 | APNIC |  AU | 12th Jul 1995 |
| 203.17.74.0/23 | 512 | APNIC | CN | 14th Apr 2011 |
| 203.17.88.0/23 | 512 | APNIC | CN | 14th Apr 2011 |
| 203.17.96.0/21 | 2k | APNIC | AU | 14th Jul 1995 |
| 203.170.131.0/24 | 256 | APNIC |  TH | 3rd Aug 2000 |
| 203.170.137.0/24 | 256 | APNIC | TH | 3rd Aug 2000 |
| 203.170.139.0/24 | 256 | APNIC | TH | 3rd Aug 2000 |
| 203.170.140.0/24 | 256 | APNIC | TH | 3rd Aug 2000 |
| 203.170.142.0/24 | 256 | APNIC | TH | 3rd Aug 2000 |
| 203.170.144.0/24 | 256 | APNIC | TH | 3rd Aug 2000 |
| 203.170.155.0/24 | 256 | APNIC | TH | 3rd Aug 2000 |
| 203.170.214.0/24 | 256 | APNIC | TH | 25th Jun 2001 |
| 203.170.225.0/24 | 256 | APNIC | TH | 25th Jun 2001 |
| 203.170.235.0/24 | 256 | APNIC | TH | 25th Jun 2001 |
| 203.170.28.0/22 | 1k | APNIC |  HK | 26th Nov 2008 |
| 203.170.60.0/23 | 512 | APNIC |  IN | 8th Dec 2008 |
| 203.170.63.0/24 | 256 | APNIC | IN | 9th Dec 2008 |
| 203.170.90.0/23 | 512 | APNIC | JP | 4th Apr 2024 |
| 203.170.92.0/22 | 1k | APNIC | AU | 4th Apr 2008 |
| 203.171.0.0/22 | 1k | APNIC | CN | 14th Apr 2011 |
| 203.171.208.0/24 | 256 | APNIC | CN | 9th Jun 2016 |
| 203.171.209.0/24 | 256 | APNIC | IN | 11th Dec 2008 |
| 203.171.218.0/23 | 512 | APNIC |  ID | 18th Dec 2008 |
| 203.171.222.0/24 | 256 | APNIC | IN | 24th Dec 2008 |
| 203.171.224.0/20 | 4.1k | APNIC | CN | 20th Apr 2006 |
| 203.171.6.0/23 | 512 | APNIC |  PH | 5th Jul 2007 |
| 203.171.64.0/19 | 8.2k | RIPE NCC |  PT | 5th Nov 2004 |
| 203.172.68.0/24 | 256 | APNIC | TH | 16th Dec 2002 |
| 203.172.92.0/24 | 256 | APNIC | TH | 16th Dec 2002 |
| 203.172.94.0/24 | 256 | APNIC | TH | 16th Dec 2002 |
| 203.173.80.0/21 | 2k | APNIC | TH | 21st Apr 2006 |
| 203.174.18.0/23 | 512 | APNIC | IN | 26th Aug 2025 |
| 203.174.28.0/23 | 512 | APNIC |  SG | 9th Apr 2008 |
| 203.174.6.0/24 | 256 | APNIC | CN | 9th Jun 2016 |
| 203.175.112.0/21 | 2k | APNIC | AU | 28th Apr 2006 |
| 203.175.16.0/20 | 4.1k | APNIC | JP | 27th Apr 2006 |
| 203.175.177.0/24 | 256 | APNIC | IN | 31st Dec 2008 |
| 203.175.192.0/18 | 16.4k | APNIC | CN | 28th Nov 2002 |
| 203.176.0.0/18 | 16.4k | APNIC | CN | 6th Apr 2011 |
| 203.176.144.0/21 | 2k | APNIC |  MY | 19th Sept 2006 |
| 203.176.160.0/21 | 2k | APNIC |  VN | 1st Dec 2006 |
| 203.176.189.0/24 | 256 | APNIC | AU | 24th Apr 2008 |
| 203.18.100.0/23 | 512 | APNIC | CN | 14th Apr 2011 |
| 203.18.105.0/24 | 256 | APNIC | CN | 14th Apr 2011 |
| 203.18.106.0/24 | 256 | APNIC | AU | 10th Aug 1995 |
| 203.18.107.0/24 | 256 | APNIC | CN | 14th Apr 2011 |