Peter:
> On 31/12/22 17:29, Sean Hennessey wrote:
> > I'm doing some testing and am trying to figure out a way to set up
> > postfix so that it won't ever send a DSN.
>
> DSNs are an important part of email but if your server sends out too
> many of them, or in two many scenarios it becomes a potential source of
> backscatter*. I suspect that your actual problem is that your server is
> sending out backscatter and you want to stop it from doing so.
>
> Unfortunately the approach you're taking will change your server from
> one that sends out backscatter to one that accepts mail and then ends up
> dropping it, which is arguably just as bad (but for different reasons).
> The correct approach is to instead try to fix your server's
> configuration so that instead of accepting mail and then sending out
> bounces in the case of invalid recipients, over quota, or just because
> of SPAM, that you instead configure your server to reject the mail as it
> is initially passed to the server. This means that you won't be a
> source of backscatter but you also won't be accepting mail and dropping it.
>
> If this is really your issue then there are many people on this list
> (myself included) who would be happy to review your config and help you
> to fix it to avoid this problem in a much better way than dropping mail.
>
> * https://en.wikipedia.org/wiki/Backscatter_(email)
I agree with this recommendation. Do not receive mail first and
then bounce.
Instead, reject invalid/over-quota/etc. recipients before receiving
mail.
Wietse
