Hi Pat,
Thanks for your response. This Exim Gateway is set up to accept mail for
which it islisted as a MX host (using @mx_any). It then scans the mail
for
SPAM using external propriatary software (SPAMSCANNER) which is
implemented using a system_filter (see below) and passes it onto another
machine (where the local mailboxes are).
The problem is that the scanning software has a bug and sometimes sends
through the original (possibly SPAMMED) message where some of the recipients
are invalid on the remote machine (which happens a lot!).
Here's how the Scanning software works (as provided by the software
people who are unwilling to fix their bug):
- a message comes into Exim
- SPAMSCANNER scans it and detects it as spam
- SPAMSCANNER modifies the message (adds headers, subject lines, etc)
- SPAMSCANNER reinjects the modified message using the command:
cat $MODIFIED_MAIL | sendmail -i -t -f $SENDER $RECEIVERS (which I
dont think can be changed)
- if the command above returns an error, then SPAMSCANNER lets the
original mail to be delivered by Exim
- if the command does not return an error, then SPAMSCANNER sends
a DISCARD command to Exim for that message, so the original message
is silently discarded.
- there is a particular case for this situation: When the email has several
receivers,
but at least one of them is invalid, then the email IS delivered to the
valid receivers
and, still, the sendmail reinjection returns an error that determines
SPAMSCANNER to
let the MTA deliver the original mail message, which causes for one of the
valid recipients
to receive the message twice: one message tagged as spam (due to
reinjection)
and one not tagged as spam (due to error returned by the sendmail
wrapper).
Here is the exim configuration for implementation of SPAMSCANNER:
---------------
system_filter = /usr/local/bin/spamfilter
system_filter_pipe_transport = spam_pipe
## Transports
spam_pipe:
driver = pipe
path = "/bin:/sbin:/usr/bin:/usr/sbin:/usr/lib:/usr/local/bin"
user = exim
With exim's high level of configurability, I though it might be possible
to get around their stupid bug. I'd appreciate your thoughts!
Thanks,
Andrew.
>From: Pat Lashley <patl+exim.users@???>
>To: Andrew Nelson <andrew__nelson@???>, exim-users@???
>Subject: Re: [Exim] How to break down CC's and process one at a time ?
>Date: Thu, 18 Dec 2003 19:29:58 -0800
>
>--On Friday, December 19, 2003 13:07:40 +1100 Andrew Nelson
><andrew__nelson@???> wrote:
>
>>Hi,
>>
>>Is it possible to configure exim to process all recipients of a message
>>(including CC and BCC addresses) seperately ?
>>
>>I'm using a system filter on a mail gateway machine that has a bug where
>>it
>>doesn't filter messages that are addressed to invalid accounts (but still
>>have valid CC's) and in a few other weird CC related situations...
>>
>>I think the problem arises whenever a destination MTA issues some
>>error message (in regards to badly formed or invalid addresses). The
>>vendor
>>doesn't want to fix it and I don't have any source.
>
>For messages coming in via SMTP, Exim doesn't use the addresses in the
>headers; it uses the addresses in the envelope. (I.e., Those provided
>via the MAIL and RCPT SMTP commands.)
>
>When invoked locally, Exim normally recieves the recipient addresses
>from the command line.
>
>The only time Exim would use the addresses in the headers is if it
>is invoked locally with the '-t' option.
>
>For more on how Exim handles messages, see Chapter 3 of the Exim docs.
>
>
>
>If you'll give us more info about the sequence of events that you
>believe leads to the problem; and an example of both the headers
>and the relevant log messages; we may be able to help you resove it.
>(We may also need to see parts of your Exim config file or the system
>filter; but I can't say for sure without the other details.)
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