[B<-ign_eof>]
[B<-no_ign_eof>]
[B<-quiet>]
-[B<-ssl2>]
[B<-ssl3>]
[B<-tls1>]
-[B<-no_ssl2>]
[B<-no_ssl3>]
[B<-no_tls1>]
+[B<-no_tls1_1>]
+[B<-no_tls1_2>]
+[B<-fallback_scsv>]
[B<-bugs>]
[B<-cipher cipherlist>]
[B<-serverpref>]
[B<-rand file(s)>]
[B<-serverinfo types>]
[B<-status>]
+[B<-nextprotoneg protocols>]
=head1 DESCRIPTION
given as a hexadecimal number without leading 0x, for example -psk
1a2b3c4d.
-=item B<-ssl2>, B<-ssl3>, B<-tls1>, B<-no_ssl2>, B<-no_ssl3>, B<-no_tls1>
+=item B<-ssl3>, B<-tls1>, B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2>
these options disable the use of certain SSL or TLS protocols. By default
the initial handshake uses a method which should be compatible with all
-servers and permit them to use SSL v3, SSL v2 or TLS as appropriate.
+servers and permit them to use SSL v3 or TLS as appropriate.
-Unfortunately there are a lot of ancient and broken servers in use which
+Unfortunately there are still ancient and broken servers in use which
cannot handle this technique and will fail to connect. Some servers only
-work if TLS is turned off with the B<-no_tls> option others will only
-support SSL v2 and may need the B<-ssl2> option.
+work if TLS is turned off.
+
+=item B<-fallback_scsv>
+
+Send TLS_FALLBACK_SCSV in the ClientHello.
=item B<-bugs>
supported cipher in the list sent by the client. See the B<ciphers>
command for more information.
-=item B<-serverpref>
-
-use the server's cipher preferences; only used for SSLV2.
-
=item B<-starttls protocol>
send the protocol-specific message(s) to switch to TLS for communication.
sends a certificate status request to the server (OCSP stapling). The server
response (if any) is printed out.
+=item B<-nextprotoneg protocols>
+
+enable Next Protocol Negotiation TLS extension and provide a list of
+comma-separated protocol names that the client should advertise
+support for. The list should contain most wanted protocols first.
+Protocol names are printable ASCII strings, for example "http/1.1" or
+"spdy/3".
+Empty list of protocols is treated specially and will cause the client to
+advertise support for the TLS extension but disconnect just after
+reciving ServerHello with a list of server supported protocols.
+
=back
=head1 CONNECTED COMMANDS
then an HTTP command can be given such as "GET /" to retrieve a web page.
If the handshake fails then there are several possible causes, if it is
-nothing obvious like no client certificate then the B<-bugs>, B<-ssl2>,
-B<-ssl3>, B<-tls1>, B<-no_ssl2>, B<-no_ssl3>, B<-no_tls1> options can be tried
+nothing obvious like no client certificate then the B<-bugs>,
+B<-ssl3>, B<-tls1>, B<-no_ssl3>, B<-no_tls1> options can be tried
in case it is a buggy server. In particular you should play with these
options B<before> submitting a bug report to an OpenSSL mailing list.
If there are problems verifying a server certificate then the
B<-showcerts> option can be used to show the whole chain.
-Since the SSLv23 client hello cannot include compression methods or extensions
-these will only be supported if its use is disabled, for example by using the
-B<-no_sslv2> option.
-
The B<s_client> utility is a test tool and is designed to continue the
handshake after any certificate verification errors. As a result it will
accept any certificate chain (trusted or not) sent by the peer. None test