From Public wiki of Kevin P. Inscoe
How to test for TLS 1.2 support
OpenSSL
$ openssl s_client -connect google.com:443 -tls1_2 | grep Protocol
...
Protocol : TLSv1.2
nmap
$ nmap -sV --script ssl-enum-ciphers -p 443 google.com | egrep 'TLS|ciphers'
...
TLSv1.2:
| ciphers:
| TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA (ecdh_x25519) - A
| TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 (ecdh_x25519) - A
| TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA (ecdh_x25519) - A
| TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 (ecdh_x25519) - A
| TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 (ecdh_x25519) - A
| TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (ecdh_x25519) - A
| TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (ecdh_x25519) - A
| TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (ecdh_x25519) - A
| TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (ecdh_x25519) - A
| TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 (ecdh_x25519) - A
| TLS_RSA_WITH_3DES_EDE_CBC_SHA (rsa 2048) - C
| TLS_RSA_WITH_AES_128_CBC_SHA (rsa 2048) - A
| TLS_RSA_WITH_AES_128_GCM_SHA256 (rsa 2048) - A
| TLS_RSA_WITH_AES_256_CBC_SHA (rsa 2048) - A
| TLS_RSA_WITH_AES_256_GCM_SHA384 (rsa 2048) - A