2020-07-27
Different SSL tests make things complex
After mention of the internet.nl tests at work I tested my webserver with the test from internet.nl and got a failed for the cipher order test. I do have the 'best' configuration according to the Mozilla SSL Configuration Generator but the test at internet.nl disagrees on this point because of the ordering of the ciphers. So with a lot of checking I now have:ssl-default-bind-ciphers ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:DHE-RSA-AES128-GCM-SHA256Which is not the order Mozilla suggests, but gives me an A+ on the Qualys SSL Server test and a good result on the standards test at internet.nl. I also found out generating my own Diffie-Hellman parameters is not good for parameter sizes of 2048 bits and up. I changed to a known-good group of 4096 bits.