Add basic spamassassin support

README.md

@@ -16,8 +16,8 @@ same level of functionality and still be able to host a complete mail server
 at little cost while running only FOSS, applying the KISS principle and being
 able to fine-tune some details if needed.
 
-Architecture
-============
+General architecture
+====================
 
 The mail infrastructure is based on a standard MTA-LDA :
 
@@ -33,6 +33,21 @@ Additional Web UI :
 
 All components are monitored by supervisord.
 
+Incoming e-mail
+===============
+
+Incoming e-mail is received by postfix, according to the workflow:
+- ``smtpd`` receives the message;
+- the domain is checked against the ``domains`` table;
+- if the domain matches an active domain or the source address is allowed relay, continue;
+- the mail is forwarded to Spamassassin, which appends some headers;
+- the mail is fowarded to Dovecot using ``lmtp``;
+- the local part and domain are checked against the ``users`` table;
+- the user quota is checked;
+- the mail is delivered to the local maildir.
+
+
+
 TODO
 ====
 
@@ -41,8 +56,9 @@ This is more of a roadmap than a proper TODO list. Please poke me or pull
 request if you would like to join the effort.
 
  - [x] Import vmm configuration files and get a simple postfix/dovecot running with SQLite.
- - [ ] Add support for spamassassin.
+ - [x] Add support for spamassassin.
  - [ ] Add support for clamav.
+ - [ ] Learn from user-defined spam or ham.
  - [ ] Draft a Web administration UI.
  - [ ] Implement basic features from the free (as in beer) poste.io.
  - [ ] Start using on a couple production mail servers.