Deploying Diffie-Hellman for TLS

[Aki Tuomi]

On 20.03.2017 13:49, Jerry wrote:
> I have been reading up on TLS and Dovecot and came across this URL:
> https://www.weakdh.org/sysadmin.html which recommended these settings
> for Dovecot. I would like to know if they are correct? Some much
> documentation on the web is pure garbage.
>
> Dovecot
>
> These changes should be made in /etc/dovecot.conf
>
> Cipher Suites
>
> ssl_cipher_list=ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA
>
> ssl_prefer_server_ciphers = yes (Dovecot 2.2.6 or greater)
>
> DH parameters
>
> #regenerates every week
> ssl_dh_parameters_length = 2048
>
> Contrary to what the site recommends, I would have thought that changes
> should be made in the "10-ssl.conf" file. I am running "Dovecot 2.2.28"
> on a FreeBSD-11 machine with OpenSSL 1.0.2k, if that makes any
> difference.
>
> Thanks
>

Hi!

It does not really matter which file you make the changes, since they
are all included into dovecot.conf.

Aki