B<openssl> B<s_client>
[B<-connect host:port>]
+[B<-proxy host:port>]
+[B<-servername name>]
[B<-verify depth>]
+[B<-verify_return_error>]
[B<-cert filename>]
[B<-certform DER|PEM>]
[B<-key filename>]
[B<-pass arg>]
[B<-CApath directory>]
[B<-CAfile filename>]
+[B<-attime timestamp>]
+[B<-check_ss_sig>]
+[B<-crl_check>]
+[B<-crl_check_all>]
+[B<-explicit_policy>]
+[B<-extended_crl>]
+[B<-ignore_critical>]
+[B<-inhibit_any>]
+[B<-inhibit_map>]
+[B<-issuer_checks>]
+[B<-partial_chain>]
+[B<-policy arg>]
+[B<-policy_check>]
+[B<-policy_print>]
+[B<-purpose purpose>]
+[B<-suiteB_128>]
+[B<-suiteB_128_only>]
+[B<-suiteB_192>]
+[B<-trusted_first>]
+[B<-no_alt_chains>]
+[B<-use_deltas>]
+[B<-verify_depth num>]
+[B<-verify_email email>]
+[B<-verify_hostname hostname>]
+[B<-verify_ip ip>]
+[B<-verify_name name>]
+[B<-x509_strict>]
[B<-reconnect>]
[B<-pause>]
[B<-showcerts>]
[B<-nbio>]
[B<-crlf>]
[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<-starttls protocol>]
+[B<-xmpphost hostname>]
[B<-engine id>]
[B<-tlsextdebug>]
[B<-no_ticket>]
[B<-sess_out filename>]
[B<-sess_in filename>]
[B<-rand file(s)>]
+[B<-serverinfo types>]
+[B<-status>]
+[B<-nextprotoneg protocols>]
=head1 DESCRIPTION
=head1 OPTIONS
+In addition to the options below the B<s_client> utility also supports the
+common and client only options documented in the
+in the L<SSL_CONF_cmd(3)|SSL_CONF_cmd(3)/SUPPORTED COMMAND LINE COMMANDS>
+manual page.
+
=over 4
=item B<-connect host:port>
This specifies the host and optional port to connect to. If not specified
then an attempt is made to connect to the local host on port 4433.
+=item B<-proxy host:port>
+
+When used with the B<-connect> flag, the program uses the host and port
+specified with this flag and issues an HTTP CONNECT command to connect
+to the desired server.
+
+=item B<-servername name>
+
+Set the TLS SNI (Server Name Indication) extension in the ClientHello message.
+
=item B<-cert certname>
The certificate to use, if one is requested by the server. The default is
with a certificate chain can be seen. As a side effect the connection
will never fail due to a server certificate verify failure.
+=item B<-verify_return_error>
+
+Return verification errors instead of continuing. This will typically
+abort the handshake with a fatal error.
+
=item B<-CApath directory>
The directory to use for server certificate verification. This directory
A file containing trusted certificates to use during server authentication
and to use when attempting to build the client certificate chain.
-=item B<-purpose, -ignore_critical, -issuer_checks, -crl_check, -crl_check_all, -policy_check, -extended_crl, -x509_strict, -policy>
+=item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>,
+B<explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
+B<-inhibit_map>, B<-issuer_checks>, B<-partial_chain>, B<-policy>,
+B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>,
+B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-no_alt_chains>,
+B<-use_deltas>, B<-verify_depth>, B<-verify_email>, B<-verify_hostname>,
+B<-verify_ip>, B<-verify_name>, B<-x509_strict>
-Set various certificate chain valiadition option. See the
+Set various certificate chain validation options. See the
L<B<verify>|verify(1)> manual page for details.
=item B<-reconnect>
show all protocol messages with hex dump.
+=item B<-trace>
+
+show verbose trace output of protocol messages. OpenSSL needs to be compiled
+with B<enable-ssl-trace> for this option to work.
+
+=item B<-msgfile>
+
+file to send output of B<-msg> or B<-trace> to, default standard output.
+
=item B<-nbio_test>
tests non-blocking I/O
inhibit printing of session and certificate information. This implicitly
turns on B<-ign_eof> as well.
+=item B<-no_ign_eof>
+
+shut down the connection when end of file is reached in the input.
+Can be used to override the implicit B<-ign_eof> after B<-quiet>.
+
=item B<-psk_identity identity>
Use the PSK identity B<identity> when using a PSK cipher suite.
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>
there are several known bug in SSL and TLS implementations. Adding this
option enables various workarounds.
+=item B<-brief>
+
+only provide a brief summary of connection parameters instead of the
+normal verbose output.
+
=item B<-cipher cipherlist>
this allows the cipher list sent by the client to be modified. Although
send the protocol-specific message(s) to switch to TLS for communication.
B<protocol> is a keyword for the intended protocol. Currently, the only
-supported keywords are "smtp", "pop3", "imap", and "ftp".
+supported keywords are "smtp", "pop3", "imap", "ftp", "xmpp",
+and "xmpp-server".
+
+=item B<-xmpphost hostname>
+
+This option, when used with "-starttls xmpp" or "-starttls xmpp-server",
+specifies the host for the "to" attribute of the stream element.
+If this option is not specified, then the host specified with "-connect"
+will be used.
=item B<-tlsextdebug>
The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
all others.
+=item B<-serverinfo types>
+
+a list of comma-separated TLS Extension Types (numbers between 0 and
+65535). Each type will be sent as an empty ClientHello TLS Extension.
+The server's response (if any) will be encoded and displayed as a PEM
+file.
+
+=item B<-status>
+
+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
+receiving 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
+applications should B<not> do this as it makes them vulnerable to a MITM
+attack. This behaviour can be changed by with the B<-verify_return_error>
+option: any verify errors are then returned aborting the handshake.
=head1 BUGS
hard to read and not a model of how things should be done. A typical
SSL client program would be much simpler.
-The B<-verify> option should really exit if the server verification
-fails.
-
The B<-prexit> option is a bit of a hack. We should really report
information whenever a session is renegotiated.
L<sess_id(1)|sess_id(1)>, L<s_server(1)|s_server(1)>, L<ciphers(1)|ciphers(1)>
+=head1 HISTORY
+
+The -no_alt_chains options was first added to OpenSSL 1.1.0.
+
=cut
projects / openssl.git / blobdiff