On Fri, Jul 23, 2021 at 09:44:38PM +0200, Thomas Walter via mailop wrote:
> Regarding RFC974
> If the list of MX RRs is not empty, the mailer SHOULD try to deliver
> the message to the MXs in order (lowest preference value tried
> first). The mailer IS REQUIRED to attempt delivery to the lowest
> valued MX. Implementors are ENCOURAGED to write mailers so that they
> try the MXs in order until one of the MXs accepts the message, or all
> the MXs have been tried.
>
> It's been a while since I looked at this, but isn't "SHOULD" a
> recommendation? I understand this collides with the next "IS REQUIRED",
> but...?
No, there is no contradiction.
I could write a mailer that starts from highest preference value to
lowest. This violates the first "SHOULD", but fulfills the second
"REQUIRED".
Bastian
--
The more complex the mind, the greater the need for the simplicity of play.
-- Kirk, "Shore Leave", stardate 3025.8
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