As provided in FICORA’s Regulation 68/2014 M, at least two and at the most ten name servers that are independent of one another must be configured to serve the domain name. This helps to ensure the functioning of the domain name in case of a failure of one of the name servers.
Name servers are independent of each other if they have
- different server devices
- different IP addresses
- separate internet connections.
Furthermore, all name servers must
- be connected to the internet
- have the name server configurations available to be verified by name server requests made by FICORA.
FICORA verifies the functionality of all name servers regularly. If one or more name servers are out of operation or the name server configurations are not correct, FICORA must send a note of this by email to the domain name registrar or to the email address of the name server administrator indicated by the registrar.
You can check the configurations by using the name server test.
Read more: Name server configurations
FICORA recommends that third parties are prevented from transferring domain name information (AXFR, DNS zone transfer protocol). Furthermore, name servers should not return a correct value if the software version is inquired. If the correct software version is returned, information security may be compromised in cases where the name server software version has a known information security issue.