Remove extra mailserver software

[katefike]

Supervisord

• Coordinates processes so they can be stopped/started together.
• supervisord.conf stores program names, a command for them, and their log files.
• It:
  • runs cron in the foreground; doesn't daemonize it
  • runs a script to start postfix.
  • sends postfix logs to stdout (maillog2stdout)

Cron

• I think every day it write postfix logs to stdout: echo '0 0 * * * root echo "" > /var/log/mail.log' > /etc/cron.d/maillog

OpenDKIM

• Provides a Domain Keys Identified Mail (DKIM) sender system for email authentication.
• Important for sending emails.

Fail2ban

• Scans logs and bans IPs if there are signs of malicious activity

RSYSLOG

• Seems to collect logs from DKIM, and then those logs go to stdout