On 30.07.2018 22:29, Aki Tuomi wrote:
On 30 July 2018 at 21:42 J Doe <gene...@nativemethods.com> wrote:
On Jul 29, 2018, at 6:02 PM, Alexander Dalloz <ad+li...@uni-x.org> wrote:
Am 29.07.2018 um 21:02 schrieb J Doe:
Hello,
I have a question regarding SSL/TLS settings for Dovecot version 2.2.22.
In: 10-ssl.conf there are two parameters:
ssl_protocols
ssl_cipher_list
ssl_protocols is commented with “SSL protocol to use” and ssl_cipher_list is
commented with “SSL ciphers to use”.
If I want to disable SSLv3, for example, do I need to use both parameters or
will disabling SSLv3 ciphers in
ssl_cipher_list do the same thing ?
So is:
ssl_cipher_list = !SSLv3
…equivalent to:
ssl_protocols = !SSLv3
ssl_cipher_list = !SSLv3
No. SSLv3 is not a cipher but a protocol.
"ssl_protocols = !SSLv2 !SSLv3" is what you want to specify.
For ciphers you could define by ssl_cipher_list see "openssl ciphers -v”
Hi Alexander and list,
I think there may be a discrepancy in the documentation.
On the wiki on the “Dovecot SSL Configuration” page [1] under the section “SSL
security settings” it says:
ssl_cipher_list = ALL:!LOW:!SSLv2:!EXP:!aNULL
In the conf.d/10-ssl.conf it states:
# SSL protocols to use
#ssl_protocols = !SSLv2
# SSL ciphers to use
#ssl_cipher_list = ALL:!LOW:!SSLv2:!EXP:!aNULL
My new question is:
1. Are the SSL/TLS protocols to use and/or exclude specified in
“ssl_protocols”, “ssl_cipher_list” or both ?
You can use SSLv2 ciphers with TLSv1.2 protocol, if enabled. ssl protocol
defines which protocol(s) to support. ssl_cipher_list defines which cipher(s)
to support. They are not the same thing.
Aki
I personally used https://www.ssllabs.com/ssltest/analyze.html when I
set up my server to get green across the board for the web server and
then used the same ciphers for Dovecot and confirmed the result with
https://github.com/drwetter/testssl.sh
ssl_min_protocol = TLSv1 # New in Dovecot 2.3 iirc.
ssl_cipher_list = "EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM
EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384
EECDH+aRSA+SHA256 EECDH+aRSA+RC4 EECDH EDH+aRSA RC4 !aNULL !eNULL !LOW
!3DES !MD5 !EXP !PSK !SRP !DSS !RC4 !SEED"
ssl_prefer_server_ciphers = yes
Good luck,
Reio
