Christian Wiese <[EMAIL PROTECTED]> wrote:
>
> [our Qmail SMTP HUB]
> 1. Fetchmail fetch the mail from POP3 mailbox at our ISP
> 2. The HUB transfers the mail to our internal Qmail server.
>
> [internal Qmail server]
> 3. our internal Qmail server delivers the mail into the local mailbox of
> "mailuser", but there are still messages that the qmail server can't
> treat local
> 4. the internal qmail server transfers the outgoing messages back to HUB
>
> [HUB]
> 5. outgoing messages will be transferd via maildirserial to our ISP's
> SMTP server
This is the fault of fetchmail. More specifically, you're using fetchmail
wrong. It has nothing to do with using "To:" instead of "Cc:" at all.
You're letting fetchmail forward popped mail through qmail, to all of
the recipients in the headers. But that's exactly what the original,
remote sender already did! So you're letting your mail server do
something which is properly none of its business.
Your only real option, if you want to use fetchmail in this setting,
is to do one of the following:
1. Scan the email's headers for specific local users addresses. This
is hard; in fact for mailing list emails or BCC-ed emails, it is
basically impossible. (If your ISP uses qmail, then you can do it
after all, since qmail writes the envelope at the top of every
message.)
2. Give each local user a separate POP account at your ISP; run
fetchmail separately for each user. Deliver to that specific
user. This prevents you from using mailboxes with addresses like
user+extension@ or user-extension@, which is a major bummer.
Since most mailers discard envelopes (or record them in a hard-to-parse
way), you will have big problems mixing a push-protocol (SMTP) with a
pull-protocol (POP3).
A better alternative is to get your ISP to set up AutoTurn for your
maildrop. In that scenario, it is the ISP's problem to keep all mail
envelopes straight. All you have to do is perform the local delivery.
Len.
--
You're deluding yourself if you think that these anti-reliability
features actually affect the spammers.
-- Dan Bernstein
