Fedora + Postfix + Dovecot + TLS/SSL + SASL

I was trying to set up Postfix with Dovecot, TLS/SSL on a new server and came across some issues so I documented them here and the install process again.

Tutorials Used

• Fedora Mail Server
• Postfix on CentOS

Install the Following

• Postfix
• Dovecot
• OpenSSL
• MailX
• SASLAuthD

Configure Postfix according to my previous article on the blog

In /etc/dovecot/conf.d/10-auth.conf add the following:

passdb {

driver = pam

}

Forward these Ports to the Mailserver if Behind Gateway

smtp: 25, 2525, 3535

smtp submission: 587

smtp over ssl: 465

pop3: 110, 995

imap: 143, 220, 993, 585

Activate and start all the above daemons using chkconfig and service saslauthd on etc.

Issue #1

Ran into a problem where Postfix would not relay mail for its own domain.

Had to add $mydomain to "mydestination" directive.

Issue #2

/var/log/maillog said mail coming from outside is going to root@platinumfactor.com even though the user exists on the system.

saslauthd service was not running. Also removed these from main.cf

smtpd_sasl_type = dovecot

smtpd_sasl_path = private/auth

Issue #3

Outgoing mail was not being delivered.

I had enabled TLS and provided a certificate to Postfix.

The client needed to be told to use SSL/TLS.

Issue #4

Set disable_plaintext_auth = yes

Incoming mail not being delivered.

Set client to use Secure POP (port 995)

Postfix + Dovecot + SSL/TLS

Ok so I was trying the next step. After getting Postfix+Dovecot working with plain text authentication. I wanted to try TLS. I saw these errors:

warning: xsasl_cyrus_server_get_mechanism_list: no applicable SASL mechanisms
fatal: no SASL authentication mechanisms

Solutions is to yum install cyrus-sasl-plain

Here is the source

TLSv1 has deprecated SSLv3, and Dovecot seems to use it by default, but if that doesn't work then edit configuration files in /etc/dovecot/ directory.

Dovecot SSL Setup:
Dovecot SSL from Official Website
Here is another very useful HOWTO guide:
CentOS + Postfix + Dovecot + SASL + SSL

To check if SSL/TLS is being used:
openssl s_client -connect mail.platinumfactor.com:995
(Thanks to mick_laptop on #dovecot on Freenode for help in testing)

Postfix with Dovecot Configuration

Without making things too complicated, all I wanted was a running mail server which will send and receive email. I decided to use Dovecot for POP3 functionality. The install is simply yum install dovecot.

These are the 3 real lines in my /etc/dovecot/dovecot.conf

protocols = imap pop3 lmtp
listen = *
!include conf.d/*.conf

Go into /etc/dovecot/conf.d and edit 10-auth.conf
Change this line:

disable_plaintext_auth = no

This is because we are not using SSL yet.

Aside from this, proper trust and relay permissions need to be set in /etc/postfix/main.cf file

I made these changes:
mynetworks_style = class
mynetworks = 192.168.1.0/24, 127.0.0.0/8


NOTE: Mailbox type needs to be changed from mbox to Maildir/ in /etc/postfix/main.cf. This caused me a lot of heartache trying to get Dovecot to work!