1 (edited by schnappi 2017-08-31 06:24:31)

Topic: Dovecot and Postfix forcing secure connections?

In the support documents iRedMail states that all clients are forced to use POP3/IMAP/SMTP services over STARTTLS for secure connections (http://www.iredmail.org/docs/allow.inse … tions.html)

Checked /etc/dovecot/dovecot.conf though and
disable_plaintext_auth= yes
was set but not
ssl=yes

This may be more of a Dovecot question but is
disable_plaintext_auth= yes
all that is needed or is
ssl=yes
needed as well to force a secure connection?

Similar issue applies to Postfix. On a new (0.9.7) and old install of iRedMail
#smtpd_tls_auth_only = yes
is commented out by default in /etc/postfix/main.cf

Shouldn't this be commented in order to force secure outgoing connections?

The reason that bring this up is that the native iPhone Mail App is weird. Still don't know if it can use STARTTLS or not. Started noticing that lots of mail users are using port 143 with TLS turned off on iPhones. Since this is the case and not honestly sure if iPhones support STARTTLS want to make sure that iRedMail is forcing secure connections. From the above settings am not sure that this is he case but also know that lots of times iRedMail has settings in places that wouldn't expect to normally look for them (aka not in /etc/postfix/main.cf)

From testing it appears that secure connections are forced despite the above but having all the iPhones set to port 143 with SSL turned off makes me want to double check.

Thanks and no rush.

==== Required information ====
- iRedMail version (check /etc/iredmail-release): 0.9.7
- Linux/BSD distribution name and version: Debian 9.1
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MariaDB
- Web server (Apache or Nginx): None
- Manage mail accounts with iRedAdmin-Pro? No
====

----

Spider Email Archiver: On-Premises, lightweight email archiving software developed by iRedMail team. Supports Amazon S3 compatible storage and custom branding.

2

Re: Dovecot and Postfix forcing secure connections?

To force IMAP/POP3 secure connections, in dovecot.conf:

ssl = required
disable_plaintext_auth= yes 

With "ssl = yes", it allows both insecure and secure connections, but with "ssl = required", only secure connections are accepted.

schnappi wrote:

Similar issue applies to Postfix. On a new (0.9.7) and old install of iRedMail
#smtpd_tls_auth_only = yes
is commented out by default in /etc/postfix/main.cf

"smtpd_tls_auth_only = yes" is used to force secure connections on port 25 if you add it in main.cf.
Please check /etc/postfix/master.cf, we have "smtpd_tls_security_level=encrypt" for submission (port 587) to force secure connection.

3

Re: Dovecot and Postfix forcing secure connections?

If use below in /etc/postfix/main.cf will it only effect outgoing SMTP connections on port 25 or will it also require delivering mail servers to deliver over TLS (thereby creating an issue for servers that cannot deliver over TLS)?

"smtpd_tls_auth_only = yes"

4

Re: Dovecot and Postfix forcing secure connections?

This parameter is for smtp auth auth_only, it only impacts client who is performing smtp auth.