Advanced Round Robin Implementation

[Rodrigo Meirelles]

    Hi friends!

    I have a bad feeling about something i'm trying to implement.

    I have to do a kind of backup system using DNS.
    I have a domain "eclipse.com.br" and its www is configured that way
below :

    www    IN    A    x.y.z.w
    www    IN    A    x.y.z.w2

I want that when somebody try to access www just the first
entry(x.y.z.w) answer, and the second entry(x.y.z.w2) just answer the
query when the first were down.
  Is it possible or not ?

  Because i think that yahoo, microsoft and others, for example, must
have many
servers to answer the dns queryes, but when one of them is down the
address must
not be the answer from a query, because the request won't get responde
and will return a "host down" status.

  I hope i could be clear...:)

  Thanks in advance!!!

Rodrigo Meirelles
rodrigo at gbl.com.br