Viktor Dukhovni <postfix-us...@dukhovni.org> writes: >> but...the way this works: the server gets offered a list of ciphersuites >> from the client, and then the server picks a ciphersuite, so without >> knowing how the server picks its ciphersuites from the client, these >> results are not clear. > > By default the server picks the client's most preferred cipher that > is also available on the server. You can set "tls_preempt_cipherlist > = yes" to have the server use its most preferred cipher supported > by the client. This could break some fragile clients that offer > ciphers (at a low preference) whose implementation is broken.
That is interesting. I tried to preempt the cipherlist and disable ECDHE to avoid the NIST curves, but couldn't get postfix to exclude that cipher using smtpd_tls_exclude_ciphers. It wasn't clear to me from http://www.postfix.org/postconf.5.html#smtpd_tls_exclude_ciphers what the correct syntax to use there is, I tried kxECDHE but that didn't work either. Do you what format those are specified in? micah
