292924Re: sender-based-routing challenge
- May 2, 2013On 5/2/2013 4:14 PM, Michael Ionescu wrote:
>Write 100 times on the blackboard: "postfix is not qmail"
> On 02.05.2013 17:57, Noel Jones wrote:
>>> prequeue proxy virusfilter [...] precludes
>>> rewriting the Received: header [...]
>>> QUESTION 1: Is this correct?
>>> QUESTION 2: Is there a definitive overview of all the ways postfix
>>> detects loops and at what stages these are employed? (I mean aside from
>>> the source code.) :-)
>>> QUESTION 3: Can one make sender-based-routing conditional [...]?
>>> QUESTION 4: Does this also work with an smtpd configured with a
>>> pre-queue proxy filter?
>>> Thanks for your insight!
>> "C" Multiple postfix instances is the preferred solution. Postfix
>> supports multiple instances on the same machine quite well. The
>> added overhead to the machine is negligible. There is some extra
>> administration, but the upside is you can easily do things that are
>> not possible (or really ugly) in a single instance.
>> -- Noel Jones
> Thanks Noel. While this may be generally correct, I come from using
> qmail and having to compensate its shortcomings by both extensive
> patching and ultimately placing multiple installations on each machine.
> I do not want to go back to having multiple MTA installations on a
> machine because of the drawbacks in administration, even in view of
> postmulti. Therefore I am explicitly asking about the other solutions I
> have in mind and am open for ones that I have not thought of.
Postfix transport features are global to each instance, and are
non-conditional. If you're using sender dependent transports, you're
going to have a hard time without multiple instances.
If you can use something else to correctly route the original mail,
you have a chance of it working without multiple instances. One
thought that comes to mind is submitting the original mail on a
specific port that has a -o
content_filter=smtp:[remote.smtp.server]. Another possibility is a
policy service that examines the detects the "special" mail through
some combination of source IP and sender, and returns FILTER
smtp:destination when appropriate.
-- Noel Jones
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