Skip to content

Mail Server (julie.mixi.cz)

Webmail (RoundCube): mail.mixi.cz

Nastavení klienta

Příjem pošty

IMAP

Preferované, zprávy zůstávají na serveru roztříděné do složek, lze používat více e-mailových klientů najednou.

  • hostname: imap.mixi.cz
  • protokol: IMAP
  • zabezpečení: SSL/TLS
  • port: 993

POP3

  • hostname: pop3.mixi.cz
  • protokol: POP3
  • zabezpečení: SSL/TLS
  • port: 995

Odesílání pošty (SMTP)

  • hostname: smtp.mixi.cz
  • protokol: SMTP
  • zabezpečení: StartTLS
  • port: 587

Components

Component Purpose
Postfix SMTP server (MTA)
Dovecot 2.4 IMAP/POP3/LMTP/ManageSieve server
rspamd Spam filtering, DKIM verification
ClamAV Antivirus scanning (via rspamd)
Redis Bayes classifier storage for rspamd
lldap LDAP authentication backend (localhost)

Mail Flow

Internet -> Postfix (SMTP/25, submission/587)
         -> rspamd milter (spam scoring, DKIM check, ClamAV)
         -> Dovecot LMTP (delivery)
         -> Sieve filtering (spam to Spam folder)
         -> Maildir storage

Hosted Domains

Configured in Postfix virtual_mailbox_domains:

mixi.cz, janna.cz, quilling.cz, vytvarnictvi.cz, g.mixi.cz, m.mixi.cz, mm.mixi.cz, t.mixi.cz, s.mixi.cz, m.janna.cz, j.janna.cz

Authentication

  • LDAP via lldap running on localhost
  • LDAP base: ou=People,dc=mixi,dc=cz
  • Filter: (&(&(objectClass=posixAccount)(accountStatus=active))(mail=%{user}))
  • Postfix SASL authentication delegated to Dovecot (private/auth socket)

Mail Storage

  • Format: Maildir
  • User: vmail
  • Home directory: from LDAP (homeDirectory attribute)
  • Mail path: ~/Maildir

Protocols & Ports

Protocol Port Notes
IMAP 143 localhost only
IMAPS 993 SSL, public
POP3S 995 SSL, public
ManageSieve 4190 personal sieve script management
ManageSieve (legacy) 2000 deprecated port

Important Config Files

Postfix

File Purpose
/etc/postfix/main.cf Main postfix configuration
/etc/postfix/vmailbox Virtual mailbox mappings
/etc/postfix/ldap-vmailbox.cf LDAP virtual mailbox lookup
/etc/postfix/ldap-valias.cf LDAP virtual alias lookup
/etc/postfix/virtual Virtual alias maps (pcre)
/etc/postfix/mynetworks Trusted networks
/etc/postfix/access Sender access control

Dovecot

File Purpose
/etc/dovecot/dovecot.conf Main dovecot config
/etc/dovecot/conf.d/90-sieve.conf Sieve plugin configuration
/etc/dovecot/conf.d/90-sieve-extprograms.conf Sieve external programs config
/etc/dovecot/private/dovecot.pem SSL certificate
/etc/dovecot/private/dovecot.key SSL key

rspamd

File Purpose
/etc/rspamd/local.d/antivirus.conf ClamAV integration
/etc/rspamd/local.d/milter_headers.conf Headers added to messages (X-Spamd-Bar, X-Virus)
/etc/rspamd/local.d/classifier-bayes.conf Bayes autolearn thresholds
/etc/rspamd/local.d/redis.conf Redis connection (localhost)

SPAM Filtering

Detection (rspamd)

rspamd runs as a Postfix milter (inet:localhost:11332) and scans all incoming mail. It adds headers:

  • X-Spam: Yes - message classified as spam
  • X-Spamd-Bar - visual spam score indicator

Bayes autolearn thresholds (in classifier-bayes.conf):

  • Spam threshold: 6.0
  • Ham threshold: -0.5

Delivery Filtering (Sieve)

Spam-flagged messages are moved to the Spam folder by a global Sieve script that runs before any personal user scripts.

Config (/etc/dovecot/conf.d/90-sieve.conf): 

sieve_script default {
  type = before
  name = spam-to-folder
  driver = file
  path = /etc/dovecot/sieve/default/spam-to-folder.sieve
}

Script (/etc/dovecot/sieve/default/spam-to-folder.sieve): 

require ["fileinto", "mailbox"];

if header :contains "X-Spam" "Yes" {
    fileinto :create "spam";
    stop;
}

After editing: sievec <file> then systemctl reload dovecot.

Spam/Ham Learning (imapsieve)

Dovecot uses imapsieve to automatically train rspamd's Bayes classifier when users move messages in/out of the Spam folder:

  • Move to Spam -> triggers report-spam.sieve -> calls rspamc learn_spam
  • Move from Spam (except to Trash) -> triggers report-ham.sieve -> calls rspamc learn_ham

Files:

File Purpose
/usr/local/lib/dovecot/sieve/report-spam.sieve imapsieve: learn spam on move to Spam
/usr/local/lib/dovecot/sieve/report-ham.sieve imapsieve: learn ham on move from Spam
/usr/local/lib/dovecot/sieve/sa-learn-spam.sh Shell wrapper: rspamc learn_spam
/usr/local/lib/dovecot/sieve/sa-learn-ham.sh Shell wrapper: rspamc learn_ham

DKIM

DKIM signing via milter on inet:localhost:12001 (configured separately from rspamd).

Personal Sieve Scripts

Users can manage their own sieve scripts via ManageSieve (port 4190):

  • Storage: ~/sieve/
  • Active script symlink: ~/.dovecot.sieve

Dovecot 2.4 Migration Notes

Dovecot 2.4 changed the sieve configuration format significantly:

  • Old format: plugin/sieve = file:~/sieve;active=~/.dovecot.sieve
  • New format: sieve_script blocks with driver, path, active_path etc.
  • The file driver with path pointing to a directory requires active_path for the symlink. Pointing path directly to a .sieve file avoids this issue.
  • Old config backup: /etc/dovecot/conf.d/90-sieve.conf.old.bad