On Sun, 2023-11-19 at 18:28 -0500, Steve Litt wrote: > > doveconf -d shows that I have no such config key as ssl_protocols, my > ssl_min_protocol is TLSv1.2, and the default ssl_cipher_list is the > following huge string: > > ALL:!kRSA:!SRP:!kDHd:!DSS:!aNULL:!eNULL:!EXPORT:!DES:!3DES:!MD5:!PSK:!RC4:!ADH:!LOW@STRENGTH > > Is the preceding the safest and most bug free, or should I modify it in > dovecot.conf? >
That's the dovecot default and it's reasonably safe. If you're the only user, you can play around with it and watch the logs to see if it changes the cipher that your mail client negotiates... but otherwise you're more likely to create obscure problems than you are to improve anything. The string above is intended to enable all ciphers and then blacklist the weak ones. A few are excluded by name, but most are excluded via the LOW and EXPORT groups. (Newer versions of OpenSSL once again do this for you; man openssl-ciphers tells me that LOW, EXPORT, kDHd, and DES have all been removed as of openssl-1.1.0.) You could try to improve this by excluding (say) the MEDIUM group, but you risk breaking clients. The list above ends with @STRENGTH to prefer stronger ciphers. That means that if you have any clients connecting with a MEDIUM strength cipher, it's because they can't use anything better -- disabling MEDIUM will cause problems. _______________________________________________ dovecot mailing list -- dovecot@dovecot.org To unsubscribe send an email to dovecot-le...@dovecot.org
