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postfix-users: Re: Is Postfix Checking Spamhaus RBL

Re: Is Postfix Checking Spamhaus RBL

From: mouss <mouss_at_nospam>
Date: Sat Oct 23 2010 - 09:29:01 GMT

Le 22/10/2010 21:42, Carlos Mennens a écrit :
> On Fri, Oct 22, 2010 at 3:34 PM, Ralf Hildebrandt
> <Ralf.Hildebrandt@charite.de> wrote:
>> Ah, maybe they're looking at all the headers, which is really stupid!
> Oh so then this is completely something configured wrong on their end
> using Microsoft Exchange, right? I just sent email from the same IP to
> my personal and friends Postfix mail servers who both use RBL checks
> to zen.spamhaus.org and they passed through fine.
>
> Can I ask what the normal procedure is for mail? If the latter IP is
> listed on a PBL but the last received IP is not, does it then allow?
> Does Postfix only look at the the most recent received client IP for
> RBL checks and thats all?

- for rejections, the PBL shouldn't be used to check IPs found in
headers at all.

- for filtering, the PBL should only be used on the last "untrusted" IP
(so you parse received headers from top to bottom and stop at the first
IP you don't "trust"). but in this case, mail should not be bounced,
because that causes backscatter. Think what happens if you forge the
sender address and try to send again. the bounce will be received by an
innocent!

For the official policy, see http://www.spamhaus.org/pbl/
(search for "Do not use the PBL in filters that ....")