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Basj
Asked: 2020-05-01 03:09:38 +0800 CST

Order of DNS A records and wilcard subdomains

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I have read Multiple wildcard dns entries and know the limitations/drawbacks of wildcard DNS entries, but I have a question about the order in which it is listed by my registrar:

example.com        A      192.0.2.1    (1)
test.example.com   A      192.0.2.2    (2)
*.example.com      A      192.0.2.3    (3)
test2.example.com  A      192.0.2.4    (4)

More precisely:

  • Am I correct that (3) won't impact (1) and so the only A record for example.com is (1)?

  • Is rule (2) overriden by rule (3), or will both rules apply for test.example.com (thus two A records for this subdomain)?

  • As (4) is listed after (3), does this mean test2.example.com will have only one A record (192.0.2.4) or two A records (both 192.0.2.3 and 192.0.2.4)?

domain-name-system nameserver a-record

1 Answers

  1. Best Answer
    1. Wildcards do not apply to the root record of the domain, so (1) will be the only A record for example.com
    2. The key point about wildcards is that they only apply for otherwise non-existent subdomains, so any queries for test.example.com and test2.example.com will be answered by (2) and (4) respectively.
    3. As I stated above, wildcards do not apply to explicitly stated subdomains, so it doesn't really matter, but DNS generally does not care about the order of records in a zone (there are some exceptions, like where the SOA record should be, and round-robin records).

    So to sum it all up, only if a query comes in for let's say foobar.example.com will it be matched with your wildcard record.

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