Inbound Mail Gateway Doubts

[Víctor Rubiella Monfort]

Hi!,

I'm working on redefine inbound mail delivery but I have some basic 
"mixconceptions".
Now I have several separate inbound servers. I want to improve deploying 
MX gateway postfix gateways, improve content filtering, etc.


First of all if someone can provide some links with more info about 
configuration and architecture on this kind of layered aproach 
(GW->postfix->dovecot) I will be very grateful :D. (something more than 
official doc and "postfix the definitive guide book" :D)

Now I have an old perl script doing a lot of task in one filter script, 
I want to refactor and optimize it.

I'm need help on concepts for "advanced content filter". First of all, 
documentation referers to Perl sample with broken link 
(http://bent.latency.net/smtpprox/. )
I see this related link 
https://stackoverflow.com/questions/40267168/advanced-content-filter-for-postfix-using-spawn-service

That links to http://www.postfix.org/spawn.8.html and 
http://www.postfix.org/SMTPD_POLICY_README.html, but this examples 
confusing me because seems related to policy filters not content_filter.

I have found quite few samples for Before-Queue filters (Milters), but 
nothing advanced samples with After-Queue filtering.

I'm looking for some code examples and best practices of advanced 
filters and how to concatenate several advanced content filters: 
reinjecting from one to another one, etc..


Thanks a lot!