A Stack Overflow thread with an example on how to check a server for SPDY support with OpenSSL:
openssl s_client -connect google.com:443 -nextprotoneg ''
The result I got from “OpenSSL 1.0.1f 6 Jan 2014” looked like this ( emphasis mine ):
CONNECTED(00000003) Protocols advertised by server: spdy/5a1, h2-14, spdy/3.1, spdy/3, http/1.1 139790806673056:error:140920E3:SSL routines:SSL3_GET_SERVER_HELLO:parse tlsext:s3_clnt.c:1061: --- no peer certificate available --- No client certificate CA names sent --- SSL handshake has read 110 bytes and written 7 bytes --- New, (NONE), Cipher is (NONE) Secure Renegotiation IS supported Compression: NONE Expansion: NONE Next protocol: (2) SSL-Session: Protocol : TLSv1.2 Cipher : 0000 Session-ID: Session-ID-ctx: Master-Key: Key-Arg : None PSK identity: None PSK identity hint: None SRP username: None Start Time: 1417496091 Timeout : 300 (sec) Verify return code: 0 (ok) ---
The “Protocols advertised by server:” is the line you need.