Another question on recursive queries

Discussion in 'DNS Server' started by Marlon Brown, Jan 17, 2007.

  1. Marlon Brown

    Marlon Brown Guest

    Can someone give me an example on when a recursive query takes place ?
    The definition below tells me that a DNS server that can't resolve the
    query, would return an error to the client saying that the address does not
    exist.
    How pratical and applicable that is ? I mean, if a DNS server doesn't know
    the address, isn't that the idea that the DNS server should forward the
    request to other DNS servers ?


    Recursive queries
    When a client system sends a recursive query to a local name server, that
    local name server must return the IP address for the friendly name entered,
    indicate that it can't find an address, or return an error saying that the
    requested address does not exist.

    Name servers do not refer the client system requesting a recursive query to
    other DNS servers. When answering recursive queries, the originating client
    does not receive address information directly from any DNS server other than
    the local name server.
     
    Marlon Brown, Jan 17, 2007
    #1
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  2. Marlon Brown

    Herb Martin Guest

    Forwarding and recursion are alternative methods to find a name a DNS
    server doesn't know directly (in its own zones or cache due to previous
    forwarding or recursion.)

    Example: Any server that can resolve The ENTIRE Internet ITSELF,
    must go to the root, find the top level (e.g., .com or .edu) DNS, from there
    find 1st level (e.g., microsoft.com, utexas.edu) etc

    This process of working down from the root (or any parent to child zones)
    is called RECURSION.

    Forwarding is handing off the entire job to another DNS server which
    either 1) Knows the answers directly, 2) Recurses physically, or
    3) Forwards to some other DNS server.

    Ultimately to resolve names through a namespace hierarchy SOME
    DNS server must be able to do recursion.

    This last paragraph says that for regularly clients the DNS servers do the
    "whole job" whether they forward to other servers, recurse, or just know the
    answer directly.
     
    Herb Martin, Jan 17, 2007
    #2
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  3. Marlon Brown

    Marlon Brown Guest

    Thanks Herb !

     
    Marlon Brown, Jan 18, 2007
    #3
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