On Fri, 28 Jun 2002, Alan J. Flavell wrote:
>
> I'm confused about the interaction of callbacks with bounces that are
> directed to us.
>
> Yesterday it appears to me that aol.com were trying to send bounces
> to us, but we were refusing them on the grounds that there was no
> valid sender in the header lines.
>
> We had callbacks enabled for aol.com, and I find if I try manually
> reproducing the effect of a callback to them I get
>
> ...
> rcpt to:<MAILER-DAEMON@???>
> 550 MAILBOX NOT FOUND
Many systems put "MAILER-DAEMON@theirdomain" as the header-sender when
they generate bounces. Many system administrators dont automatically set
up this box. so this is simply a case of a (bounce) message being swnt
with an invalid header sender. Nothing precuiliar there.
Validating header senders with a callback is a bit extreme though.
Usually bounce messages with have an envelope sender of <> which is
always automatically considered 'valid' by exim.
>
> Any comments to help me understand what's going on, please? Should
> exim be verifying the sender of bounces via callback? Ought the other
> partner to refuse such a callback?
>
> (This is tied up with a collateral spam incident, but dealing with
> that is out of our hands really..)
>
>
> --
>
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>
>
