Postfix and Mailscanner sitting in a tree k-iss-ing

[Drew Marshall]

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paddy wrote:

 On Thu, Dec 30, 2004 at 06:00:20PM +0000, Julian Field wrote:
  

 Very good summary. You just saved me a whole load of typing and thinking.
I would have to pipe messages out of Postfix, implementing my own entire
robust queueing system, process them and then feed them back into
Postfix by some "sanctioned" method, with another queue to buffer the
MailScanner-->Postfix interface.
Very messy.
    

 Yes and no.

Aside from the verboten sharing of files, what other interactions does
Mailscanner have with postfix ? I'm guessing maybe some but not a lot.
  

AFAIK none. Mail picked up from a directory (AKA Queue file. Lets not
mess about here it's a directory. Not much else ;-) ) processed and
returned to another one (Ok slightly simplistic but you get the idea).

 I'm not saying the problem you describe is totally trivial, just that its
not MailScanner's problem: a seperate app could provide this service.
Indeed, this is surely the point about 'you could add another MTA, but
why would you want to do that?'  But, in the postfix design this seems
to be encouraged, or perhaps I have misunderstood?
  

Hmm, encouraged by one party yes but not by the other. Personally I
belong to the old school of customer service that states that the fewer
number of cogs in a process the less likely it is to break. I do know of
someone who has done just that and installed a stripped down Exim install
as the interface for Postfix, listening on another port. To me that seems
daft. You might as well install Exim to do the whole job (Something I
never quite managed, obviously being thick. All those routers...)

 MailScanner provides an interface to postfix that happens not to be
supported by the postfix people, but the impression I get is that users
like it. We're already agreed that there are (perhaps hypothetical)
options that would enjoy only the sanctified API, however bloated.

  

 Incidentally, something in the same vein has already been done for
Communigate Pro, but I have never looked at that. I suspect (though
without evidence either way) that it is not approx. 100% robust in the
face of a concerted DoS attack. I go to some lengths to try to ensure
that, when under attack, the MTA will give out long before MailScanner does.
    

 Agreed, failure modes are at least as important as 'ordinary' operation with
this kind of thing.

To keep your head when all around are losing theirs :)

  

 Thanks for your well thought-out explanation, Drew!
    

 Thank you both for having the patience to go over this with me.
  

A pleasure :-)

Have a Happy New Year all

Drew

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