> From: openssl-users On Behalf Of Rajeswari K > Sent: Monday, February 02, 2015 22:17 > Thanks for responding. Following is the output printed by openssl > ./openssl req -in csr.csr -noout -text <snip> > Subject Public Key Info: > Public Key Algorithm: id-ecPublicKey > Public-Key: (256 bit) > pub: > > ASN1 OID: prime256v1 Yes, that is named form. Then I don't know what the problem is. Generic debugging advice, if you haven't tried these already: Does the problem occur with s_client to your server? Does the problem occur with s_client to s_server using the same cert&key, cipherlist (if not default) and same or reasonable tmp-ECDH? Actually, that's a thought. You said your server uses tmp-ECDH callback; does that (always) provide a curve/parameters object that *has* an OID which maps to one of the TLS standard curves in 4492 (and one specified in the client hello but your earlier trace looked like the client specified all). s_server *only* supports named curves (and defaults to p256).