Re: [Exim] Avoiding frozen spam

At 11:09 -0700 2003/10/07, Mark Edwards wrote:
>
>You guys are suggesting a callout, but I don't want to reject all mail
>that doesn't have a valid return address. Won't a callout interfere
>with email from places that intentionally have a bunk return address to
>prevent people from replying?

oh well, I haven't yet seen a real no-reply address that will fail
callout (that is that will fail a bounce *attempt*). If there is one,
then it is bound to carry no useful information (as it can be lost
with no warning).
And since that is the case, they should really use a null sender.
I have a no-reply address that will accept a callout but no data after it...


>
>In any case, you are saying not to generate the bounce messages in the
>first place. The only alternatives I can see are accepting the spam and
>deleting it manually (let's leave that option out for the purposes of
>this discussion) or just auto-trashing the spam with no warning to anyone.
>
>If I don't generate the bounce messages, I don't need to do the callout
>to prevent the bounce messages from getting frozen.

no, wait a second. If you do a callout to prevent bounce messages
from getting frozen, you are using it for the least useful, actually
most annoying purpose.
If you do that what about I start sending 10K emails forging your
address around the world and see how you like that?

>
>So, I'm puzzled as to what is being recommended here. If a callout is
>going to trash legitimate email, I don't want to do it. Perhaps I could
>only do a callout for spam-bounce messages? But you're rejecting the
>entire bounce-message concept, so now I'm confused.


My recommendation is to do what you can at SMTP (that is reject what
you reckon is spam) and keep the rest, maybe flagged.
Exim is powerful, to the point that I presently get one or two spam a
day between my three accounts (more if you consider aliases). The
recipe? Use acl variables to build a score based on RBLs, HELO/DNS,
IDENT and leave the sender callout as a last resort (when the other
criteria are not decisive). For certain account I do not even reject
on the basis of a single RBL (or even callout) with no other reason.
This is complemented by blacklists and whitelists (for those senders,
or recipients, for which I cannot even accept the possible temporary
error of a DNS defer result).

>I'm not looking to start a shouting match about spam politics here. The
>goal is to improve spam management without blackholing legitimate email.
>
>Thanks for the help!

Giuliano