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Next: Recursion Up: DNS and BIND Primer Previous: Answer Types

Name Resolution Process

  1. The resolver (dns client) sends a DNS query to the first name server listed in the resolv.conf file (Linux/Unix).
    If there is no response in n seconds (see chart page [*], try next server in resolv.conf. . .
  2. If the name server is authoritative or has a cached answer it answers the query directly.
  3. If the name server can not resolve the query, it sends a query to a root name server which is authoritative for or knows of authoritative servers for all top level domains.
  4. The root server answers with a referral to the name of the top level domain server for the requested domain or possibly the next second-level domain name server.
  5. The local name server then queries the name server it received from the last query and the process continues until the final answer is received. The answer is sent back to the client.

Pete Nesbitt 2012-04-23