Re: [exim] two stage virus scan

Chris Lightfoot wrote:
>
> The difficulty here is that in the current email
> architecture the only person who can detect whether a
> bounce is valid is the (alleged) sender. A third-party
> mail server *cannot* determine whether a given bounce is
> valid or not. Dropping delivery error notifications on the
> floor based on some heuristic is incorrect; refusing mail
> transactions from hosts purely because they correctly
> process delivery error notifications is idiotic. (I hope,
> by the way, that you fully inform your users that you are
> programming your mail server to discard information about
> whether their mail got through or not.)

You're just plain wrong here, Chris. Once you've accepted a message,
it's your responsibility. If you choose to accept messages and then scan
for viruses after acceptance, the only responsible option available is
to freeze/quarantine the virus on your own system, and have your own
staff (either the recipient or someone on your postmaster staff) review
the quarantine manually. As you point out, simply dropping them on the
floor without notification to the sender is unreasonable, but bouncing a
virus (or a virus notification) to an unverified and very likely forged
sender is just as unreasonable, if not more so.

- Marc