Setting up simple mail server with sendmail + dovecot + squirrelmail on fedora 26

Sendmail is a MTA (Mail Transfer Agent) in Linux used to send emails. Dovecot is a mail authentication software. Squirrelmail is a mail user agent similar to an email client.

1. Install the packages:

dnf install sendmail sendmail-cf sendmail-doc cyrus-sasl-{lib,plain} dovecot squirrelmail

2. Configure sendmail:

Edit /etc/mail/sendmail.mc:

• Line 122: set DAEMON_OPTIONS('Port=smtp,Name=MTA')dnl
• Line 161: set LOCAL_DOMAIN('server.sand.box')dnl

Build the configuration file:

cd /etc/mail
make all

Restart sendmail:

systemctl restart sendmail

3. Configure Squirrelmail:

cd /usr/share/squirrelmail/config/
./config.pl

Set organization preferences and server settings as needed.

4. Configure Dovecot:

Edit configuration files in /etc/dovecot/:

• 10-mail.conf: set mail_location = maildir:~/Maildir
• 10-ssl.conf: set ssl = yes
• 10-auth.conf: set disable_plaintext_auth = no and auth_mechanisms = plain login
• dovecot.conf: set protocols = imap pop3 lmtp and listen = *

Restart services:

systemctl restart dovecot; systemctl restart sendmail; systemctl restart httpd

Now you can access Squirrelmail from https://localhost/webmail.

To forward root emails to another user:

formail -s /usr/sbin/sendmail -oi -t < /var/mail/root