Re: header_checks PREPEND

From: mouss (no email)
Date: Wed Nov 01 2006 - 11:16:21 EST

  • Next message: mouss: "Re: Postfix setting? or Spam Assassin?"

     wrote:
    > The postfix server in question simply passes inbound valid mail to our exchange server
    > and passes outbound mail to an external mail service run by messagelabs, messagelabs
    > then passes it on to the outside world.
    >
    > It's the messagelabs server that puts in the X-SpamReason header. I need to catch
    > this X-SpamReason value and if it's >0 & <= 4 do nothing with it, just pass it
    > onto exchange.
    >
    > If the X-SpamReason header value is > 4 & < 7 prepend the subject with [SPAM] and
    > pass it to exchange as normal, letting the user set a rule in outlook for this if
    > they wish.
    >
    > X-SpamReason > 7 will result in the mail getting redirected to a quarantine address
    > in exchange.
    >
    > I've tried to google software that will let me do this, but I'm not having much luck.
    > I had thought about setting up my own content_filter but like yourself I considered it
    > overkill.
    >
    > Would procmail/maildrop work with the situation I described above ? I don't have any
    > experience of procmail or maildrop.
    >
    >

    yes. Here is a summary (with maildrop)
    - use transports to deliver mail for @domain.example to maildrop
    - maildrop
        * checks the spam header.
        * maildrop gets the subject
        * if spam, maildrop runs reformail to change the subject
         * maildrop forwards mail to .example
    - use transports to forward @done.domain.example to your exchange server
    - use generic to rewrite @done.domain.example to @domain.example

    but this sounds like "trying to avoid a content_filter at all expenses"!
    see below.
    > If anyone knows any software which will do what I'd appreciate a heads up. We aren't doing
    > our own spam/virus scanning so I can't rewrite the subject with spamassassin.
    >
    >

    you could run SA with just one rule: match the X-SpamReason header and
    score it enough to trigger sbject rewrite. but there is no need to use
    SA just for this.

    Instead,
    - write a script to check the spam header and modify the subject accordinly
    - use smtpprox to run the script

    If you are not confortable writing scripts or maildrop/procmail recipes,
    here is a postfix-only way. Convoluted but...

    - add an smtpd (let's say on 127.0.0.1:10099) and a corresponding
    cleanup to your master.cf. This cleanup has a header check that always
    tags the subject:
    /^Subject: (.*)/ REPLACE Subject: [Spam] $1

    - In the "standard" header_checks, use
    /X-SpamReason: Yes, hits=([1..4]\.[0-9]*).*required/ FILTER
    scan:[127.0.0.1]:10099
    where scan is defined as a filtering transport in master.cf

    - the smtpd on 10099 has no content_filter, does no unknown recipient
    validation, ... (see the FILTER_README for examples of configuration.
    copy options of the smtpd on 10025 from there).


  • Next message: mouss: "Re: Postfix setting? or Spam Assassin?"





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