The accessibility and validity of all nameservers is checked continuously. A nameserver is valid if it passes the following checks:
- Respond time within 3 seconds
- NXDOMAIN-Reply to a query of a non existent domain (i.e. xxx.example.com)
Correct resolution of wikileaks.org, youporn.com, archive.org, rotten.com and thepiratebay.org.
The results are checked against the result of the reference nameserver (
- Response for www.dnssec-tools.org with AD Bit set
Use the Global DNS Tester to test multiple servers for a specific hostname.
If you have any suggestions how to improve this service, please contact me via email/jabber.
To calculate the reliality of a nameserver the number of successful tests are divided by the total number of tests. A cronjob delete all tests older than 30 days once per day. Possible causes for a drop of the reliability are:
- Network/Connectivity problems
- The IP address of a checked domain changes and differs from the result of the reference nameserver unless the TTLs expired.
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