Also reorder preferences to prefer prime curves to binary curves, and P-256 to everything else.
The result:
$ openssl s_server -named_curves "auto"
This command will negotiate an ECDHE ciphersuite with P-256:
$ openssl s_client
This command will negotiate P-384:
$ openssl s_client -curves "P-384"
This command will not negotiate ECDHE because P-224 is disabled with "auto":
$ openssl s_client -curves "P-224"
Reviewed-by: Kurt Roeckx <kurt@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
de57d23729