[OpenIndiana-discuss] OT postfix v.s Qmail

[låzaro]

answer in lines...

Thread name: "Re: [OpenIndiana-discuss] OT postfix v.s Qmail" 
Mail number: 22 
Date: Tue, Apr 24, 2012 
In reply to: Gary Gendel <gary at genashor.com> 
>
> Låzaro,
> 
> Thanks for the pointer.  Policy-light is much closer to spamdyke's
> capabilities than postfix is.  The big difference is that qmail uses
> process chaning and passes information via environment variables
> where postfix uses a database to provide the information and proxies
> to the modules.  As it hasn't reached version 1 yet, the system is
> still in flux.
> 
> The advantage of qmail's approach is that the work is partitioned by
> executing functionality as needed and the chain is completely
> segregated from other sessions.  Postfix requires executing
> auxiliary services which requires either a proliferation of smaller
> databases or one large database with access locks.
I"m not clear just now but I think, when Postfix make querry to BL DNS
him don't use database, just make a lookup, repeat "I'm not pretty shure
about that". Anyway... I think who use database is more "better" than
system variables, their data don't go flying when the come the blackuots.

Also: "more services, more separate, more secure". Of corse, in the
light-weight balancing load, Qmail have the novell price (use it onle
when needed) but I don't change lightness for security. Also repeat:
I love Qmail, but is a very good idea with very old implementation(s).


> 
> The advantage of postfix's approach is the single arbitrator of what
> is going on so the modules are stateless.  Qmail relies on the
> handoff continue where the previous one left off.  If they read from
> the socket (which is connected to stdin), then they must convey this
> information (using stdout) to the next in the sequence. Thus it must
> store this information if required.  This becomes an issue when
> dealing with a module like SpamAssassin.  In this case, the
> interface, saves the necessary information into a file, let's
> spamassassin process it, and then replay the file to the next item
> in the chain.  On the other hand, postfix's modules rely on postfix
> to collect all the information they need to do their job apriori.
For fight with spam just reject_rbl is enough. Usage of spam-asassim is
very wheigth, heavy (for my old comuter server) the load growht much,
much better consult DNS-BL direct, also more updated. Policyd just done
that but also use cache and save bandwith (very important here) Policyd
also make tarpiting, is an all in one. Very good, but.. if their fail,
all the mail will bty rejected, that never happen to me but is a
posibility...



> 
> This is been a very useful side discussion for me.  We all have our
> biases, mine is based upon familiarity but I can see the writing on
> the wall so this is just an intellectual discussion.
> 
> Gary