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Fedora Email

The Fedora 25 email server is running the Postfix MTA (Mail Transfer Agent) for SMTP. This is usually done with TCP port 25 and TCP port 465.

The Dovecot IMAP and POP3 server also could be running, which allows mail retrieval from a server. IMAP usually uses TCP 143 for unsecure connections, and 993 for IMAP over SSL. POP3 uses TCP 110 for unsecure connections, and TCP 995 for POP3 over SSL/TLS.

Postfix

Postfix has literally hundreds of config options. These options are usually stored in the /etc/postfix directory. The main.cf files contains config options, and master.cf which specifies what services it should run.

Postconf

The command-line tool postconf is usually used to modify the master.cf file rather than editing it by hand.

Service management

Postfix seems to do its own service management using the postfix command.

Hardening and DSAs

CVEs for Postfix

  • https://linux-audit.com/postfix-hardening-guide-for-security-and-privacy/

Dovecot

Dovecot config files are stored in /etc/dovecot/dovecot.conf and /etc/dovecot/conf.d/*

Hardening and DSAs

Don't put the dovecot user in the mail group! Info

Users

Users are being pulled over LDAP from the Windows AD machine.

DNS

Mail servers usually require special A and MX records.

Resources

  • https://wiki.archlinux.org/index.php/Virtual_user_mail_system_with_Postfix,_Dovecot_and_Roundcube
  • https://www.digitalocean.com/community/tutorials/how-to-set-up-a-postfix-e-mail-server-with-dovecot