The .LU registry requires that name servers be properly preconfigured before delegating the domain. This rule applies to both domain registration and modification of name servers. You can also refer to our Wiki: LU - HEXONET Wiki.
The registry provides a web-based tool to check the DNS setup for a domain. The test shows whether there are setup errors for one or more nameservers:
https://dns.lu/en/domains/name-server-test
You must enter both the domain and the nameservers for the test, as shown in the picture below:
Technical name server requirements
The .LU registry requires that:
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The name servers are authoritative for the requested domain.
- The name servers match the IP address provided.
- The name servers are listed as name servers (IN NS record) in the DNS zone of the domain.
- The name provided for the server names is a Canonical Name, not CNAME record.
Also, different validation steps apply depending on the name server configuration submitted:
If the name server is part of the domain name, for instance ns1.example.lu is part of example.lu, then:
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An 'A' query requesting the name server's name is sent to the server's IP address.
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The server's response must be authoritative and contain the server's IP address, and not return the name of the server in the form of an alias.
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An 'NS' query requesting the domain name in question is sent to the server's IP address.
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The response must be authoritative and contain the server's name.
If the server name is not part of the domain, then:
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An 'NS' query requesting the domain is sent to the IP address obtained by normal resolution of the server name (and not the IP address indicated in the 'IP Address' field).
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The response must be authoritative and contain the queried server's name.
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An 'A' query requesting the server name is sent to any server name that can handle recursive resolutions.
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The response must contain the IP address of the server name as indicated in the 'IP Address' field, and the server name must be a Canonical Name (CNAME).
If there is a failure, the servers are considered non-functional.