TLS 1.2 が、サポートされたのは、OpenSSL version 1.0.1 からだと思うのですが、お使いの環境の OpenSSL のバージョンは、いくつでしょうか?
確認方法:
openssl s_client -connect www.google.com:443 -tls1_2
対応している場合
CONNECTED(00000003)
depth=2 OU = GlobalSign Root CA - R2, O = GlobalSign, CN = GlobalSign
verify return:1
depth=1 C = US, O = Google Trust Services, CN = Google Internet Authority G3
verify return:1
depth=0 C = US, ST = California, L = Mountain View, O = Google LLC, CN = www.google.com
verify return:1
---
Certificate chain
0 s:/C=US/ST=California/L=Mountain View/O=Google LLC/CN=www.google.com
i:/C=US/O=Google Trust Services/CN=Google Internet Authority G3
1 s:/C=US/O=Google Trust Services/CN=Google Internet Authority G3
i:/OU=GlobalSign Root CA - R2/O=GlobalSign/CN=GlobalSign
---
Server certificate
-----BEGIN CERTIFICATE-----
(省略)
-----END CERTIFICATE-----
subject=/C=US/ST=California/L=Mountain View/O=Google LLC/CN=www.google.com
issuer=/C=US/O=Google Trust Services/CN=Google Internet Authority G3
---
No client certificate CA names sent
Peer signing digest: SHA256
Server Temp Key: ECDH, P-256, 256 bits
---
SSL handshake has read 2986 bytes and written 415 bytes
---
New, TLSv1/SSLv3, Cipher is ECDHE-RSA-AES128-GCM-SHA256
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
SSL-Session:
Protocol : TLSv1.2
Cipher : ECDHE-RSA-AES128-GCM-SHA256
Session-ID: 9279A0635D520A443EB6E4F8B49571E05E678212FDB4E2FEF21498BAEED9A042
Session-ID-ctx:
Master-Key: B0E2902118E3182E9ADEBEB731C0FF080580986DFC9F90242EA64DF5C9A37408862B28EE0AC285E17EDDE711D2006B8A
Key-Arg : None
Krb5 Principal: None
PSK identity: None
PSK identity hint: None
TLS session ticket lifetime hint: 100800 (seconds)
TLS session ticket:
0000 - 00 03 c1 16 a8 05 68 cb-be 36 04 0d 94 4a 5e e1 ......h..6...J^.
0010 - f7 94 06 7f 69 62 8c 3b-26 df 36 c1 fc 94 2a 7b ....ib.;&.6...*{
0020 - db 52 9e 7d 5c 9a 00 99-00 c8 2d 6b eb 0d c2 1f .R.}.....-k....
0030 - af 0d 7a 4f d3 5b 5c c2-b3 5b c7 64 52 d0 e0 2f ..zO.[..[.dR../
0040 - 19 5e ac d9 62 db 18 11-19 af 4d 26 89 79 20 48 .^..b.....M&.y H
0050 - 2f ae 8a 56 d7 0e 51 11-48 6c 59 26 73 48 c9 a0 /..V..Q.HlY&sH..
0060 - 79 38 de 19 ec 0a 67 8a-40 f9 ed 16 9f 90 0b dd y8....g.@.......
0070 - b9 3b c2 b7 26 e6 7d d2-9b d5 2b b1 53 ed 9f f7 .;..&.}...+.S...
0080 - ef 77 d5 2b 7a 03 05 4d-43 c9 6d 42 51 47 d3 ac .w.+z..MC.mBQG..
0090 - 62 28 f8 35 d0 e0 be 09-56 bc c9 fe 98 83 c1 cc b(.5....V.......
00a0 - b3 af 04 7e 67 fb ca 7e-7e b3 0f 80 5d 8f 01 18 ...~g..~~...]...
00b0 - 93 50 10 b1 5b 8d ae 95-2e 67 8b 30 72 a1 d8 af .P..[....g.0r...
00c0 - 93 25 43 90 df 8d e5 a6-7e 57 96 85 6f 24 c0 1e .%C.....~W..o$..
00d0 - 6b 86 ee 9d 9c k....
Start Time: 1537337921
Timeout : 7200 (sec)
Verify return code: 0 (ok)
---
(以下略)
のような結果で、
SSL-Session:
Protocol : TLSv1.2
Cipher : ECDHE-RSA-AES128-GCM-SHA256
Session-ID: 9279A0635D520A443EB6E4F8B49571E05E678212FDB4E2FEF21498BAEED9A042
Session-ID-ctx:
とあります。
対応していない場合
$ openssl s_client -connect www.google.com:443 -tls1_2
unknown option -tls1_2
usage: s_client args
オプションのエラーになります。