Postfix + dovecot setup

[Gregory Sloop]

TM> I'm trying to clarify the various ways in which I could set up
TM> Postfix + Dovecot + SpamAssassin under CentOS-7,
TM> and I'd welcome any comments on the following remarks.

TM> As far as I can see there are 3 standard ways of setting this up:
TM>   1. Use amavisd
TM>   2. Use dovecot + pigeonhole/sieve
TM>   3. Use spamass-milter

TM> At present I'm following (2), but am thinking of going over to (1),
TM> since this seems simpler.
TM> (Amavisd wasn't available when I set up CentOS-7, so I didn't consider it
TM> then.)

TM> It seems to me that (2) is using dovecot in a slightly odd way,
TM> since as far as I can see dovecot normally takes email from ~/Maildir/cur/
TM> and then moves marked spam.

TM> I'm not quite sure if (3) is a genuine alternative,
TM> or if it is why it is not the standard?
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spampd [I'm doing it under Ubuntu, but used to do it under RHEL]
spdmpd is a pre-accept daemon that processes for SA - where you can simply reject mail with SA scores higher than X, instead of simply tagging them as spam.

Typical is: 
Score above 10, reject before MTA acceptance. 
Score from 5-10, tag as spam, but accept for delivery.

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However, I'm working on moving to amavisd instead of spampd. But it's almost no extra work to use spampd vs SA alone and amavisd seems like more work than spampd. [It's certainly more complex.]

YMMV.

-Greg