Marten Lehmann wrote:
> Hello,
>
> our mailserver refused a certain email of a customer and when we tried
> to track down the problem, we noticed that the server of the server
> replied to our verification like this:
>
> mail from: <>
> 250 Ok
> rcpt to: test@???
> 450 <test@???>: Recipient address rejected: Greylisted for 300
> seconds (see http://...)
>
> Might this be the reason for the sender verify to fail? If yes, what can
> we do against it?
>
> Regards
> Marten
>
The above is only one of many false-positives.
'raw' sender verify should not be relied on as an all-or-nothing test.
The Exim MLM on sesame, for example fails sender verify at 'recipient', yet is
certainly on MY list of 'good guys'.
You need either a more sophisticated crafting of sender verification, a
'weighted' reaction to its return codes, or both.
Else use it only to add warning headers, not to reject.
Bill
