Re: Multiple Mail domains for reverse ptr records? I'm confused

From: Wietse Venema (no email)
Date: Fri Nov 27 2009 - 13:18:15 EST

  • Next message: Stan Hoeppner: "Postfix Deployment"

    Wietse Venema:
    > Greg A. Woods:
    > > There _should_ be one PTR for every _valid_ hostname using a given IP
    > > address.
    >
    > Statements such as above remind me of silly knights fighting windmills.
    >
    > There is a difference between "right" and "useful", and it even
    > depends on where they are used - server or client side.
    >
    > Multiple server A records are useful. More in the case of HTTP,
    > less in the case of SMTP which uses indirection via MX records.
    > (For a discussion about domain-in-a-box applications, see some
    > actual measurements that I did earlier this year).
    >
    > One PTR per A record is not useful. The server end will not know
    > what client name to use.

    That is, one PTR per A record, in the case of multiple A records
    for the same IP address.

    > On the other hand, it is right when every PTR record has a matching
    > A record that resolves to (among others) the PTR record's address.
    >
    > Wietse
    >
    >


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