=head1 NAME
+openssl-s_client,
s_client - SSL/TLS client program
=head1 SYNOPSIS
B<openssl> B<s_client>
[B<-help>]
[B<-connect host:port>]
+[B<-bind host:port>]
[B<-proxy host:port>]
+[B<-proxy_user userid>]
+[B<-proxy_pass arg>]
[B<-unix path>]
[B<-4>]
[B<-6>]
[B<-certform DER|PEM>]
[B<-key filename>]
[B<-keyform DER|PEM>]
+[B<-cert_chain filename>]
+[B<-build_chain>]
+[B<-xkey>]
+[B<-xcert>]
+[B<-xchain>]
+[B<-xchain_build>]
+[B<-xcertform PEM|DER>]
+[B<-xkeyform PEM|DER>]
[B<-pass arg>]
[B<-CApath directory>]
[B<-CAfile filename>]
+[B<-chainCApath directory>]
+[B<-chainCAfile filename>]
[B<-no-CAfile>]
[B<-no-CApath>]
[B<-requestCAfile filename>]
[B<-verify_hostname hostname>]
[B<-verify_ip ip>]
[B<-verify_name name>]
+[B<-build_chain>]
[B<-x509_strict>]
[B<-reconnect>]
[B<-showcerts>]
[B<-crlf>]
[B<-ign_eof>]
[B<-no_ign_eof>]
+[B<-psk_identity identity>]
+[B<-psk key>]
+[B<-psk_session file>]
[B<-quiet>]
[B<-ssl3>]
[B<-tls1>]
[B<-dtls1>]
[B<-dtls1_2>]
[B<-sctp>]
+[B<-sctp_label_bug>]
[B<-fallback_scsv>]
[B<-async>]
[B<-max_send_frag>]
[B<-sigalgs sigalglist>]
[B<-curves curvelist>]
[B<-cipher cipherlist>]
+[B<-ciphersuites val>]
[B<-serverpref>]
[B<-starttls protocol>]
[B<-xmpphost hostname>]
+[B<-name hostname>]
[B<-engine id>]
[B<-tlsextdebug>]
[B<-no_ticket>]
[B<-sess_out filename>]
[B<-sess_in filename>]
-[B<-rand file(s)>]
+[B<-rand file...>]
+[B<-writerand file>]
[B<-serverinfo types>]
[B<-status>]
[B<-alpn protocols>]
[B<-nextprotoneg protocols>]
-[B<-ct|noct>]
+[B<-ct>]
+[B<-noct>]
[B<-ctlogfile>]
[B<-keylogfile file>]
[B<-early_data file>]
+[B<-enable_pha>]
[B<target>]
=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
+common and client only options documented
in the "Supported Command Line Commands" section of the L<SSL_CONF_cmd(3)>
manual page.
This specifies the host and optional port to connect to. It is possible to
select the host and port using the optional target positional argument instead.
-If neither this nor the target positonal argument are specified then an attempt
+If neither this nor the target positional argument are specified then an attempt
is made to connect to the local host on port 4433.
+=item B<-bind host:port>]
+
+This specifies the host address and or port to bind as the source for the
+connection. For Unix-domain sockets the port is ignored and the host is
+used as the source socket address.
+
=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<-proxy_user userid>
+
+When used with the B<-proxy> flag, the program will attempt to authenticate
+with the specified proxy using basic (base64) authentication.
+NB: Basic authentication is insecure; the credentials are sent to the proxy
+in easily reversible base64 encoding before any TLS/SSL session is established.
+Therefore these credentials are easily recovered by anyone able to sniff/trace
+the network. Use with caution.
+
+=item B<-proxy_pass arg>
+
+The proxy password source, used with the B<-proxy_user> flag.
+For more information about the format of B<arg> see the B<PASS PHRASE ARGUMENTS>
+section in L<openssl(1)>.
+
=item B<-unix path>
Connect over the specified Unix-domain socket.
=item B<-servername name>
Set the TLS SNI (Server Name Indication) extension in the ClientHello message to
-the given value. If both this option and the B<-noservername> are not given, the
-TLS SNI extension is still set to the hostname provided to the B<-connect> option,
-or "localhost" if B<-connect> has not been supplied. This is default since OpenSSL
-1.1.1.
+the given value.
+If B<-servername> is not provided, the TLS SNI extension will be populated with
+the name given to B<-connect> if it follows a DNS name format. If B<-connect> is
+not provided either, the SNI is set to "localhost".
+This is the default since OpenSSL 1.1.1.
+
+Even though SNI should normally be a DNS name and not an IP address, if
+B<-servername> is provided then that name will be sent, regardless of whether
+it is a DNS name or not.
-Even though SNI name should normally be a DNS name and not an IP address, this
-option will not make the distinction when parsing B<-connect> and will send
-IP address if one passed.
+This option cannot be used in conjunction with B<-noservername>.
=item B<-noservername>
The private format to use: DER or PEM. PEM is the default.
+=item B<-cert_chain>
+
+A file containing trusted certificates to use when attempting to build the
+client/server certificate chain related to the certificate specified via the
+B<-cert> option.
+
+=item B<-build_chain>
+
+Specify whether the application should build the certificate chain to be
+provided to the server.
+
+=item B<-xkey infile>, B<-xcert infile>, B<-xchain>
+
+Specify an extra certificate, private key and certificate chain. These behave
+in the same manner as the B<-cert>, B<-key> and B<-cert_chain> options. When
+specified, the callback returning the first valid chain will be in use by the
+client.
+
+=item B<-xchain_build>
+
+Specify whether the application should build the certificate chain to be
+provided to the server for the extra certificates provided via B<-xkey infile>,
+B<-xcert infile>, B<-xchain> options.
+
+=item B<-xcertform PEM|DER>, B<-xkeyform PEM|DER>
+
+Extra certificate and private key format respectively.
+
=item B<-pass arg>
the private key password source. For more information about the format of B<arg>
=item B<-CApath directory>
The directory to use for server certificate verification. This directory
-must be in "hash format", see B<verify> for more information. These are
+must be in "hash format", see L<verify(1)> for more information. These are
also used when building the client certificate chain.
=item B<-CAfile file>
A file containing trusted certificates to use during server authentication
and to use when attempting to build the client certificate chain.
+=item B<-chainCApath directory>
+
+The directory to use for building the chain provided to the server. This
+directory must be in "hash format", see L<verify(1)> for more information.
+
+=item B<-chainCAfile file>
+
+A file containing trusted certificates to use when attempting to build the
+client certificate chain.
+
=item B<-no-CAfile>
Do not load the trusted CA certificates from the default file location
=item B<-showcerts>
-Display the whole server certificate chain: normally only the server
-certificate itself is displayed.
+Displays the server certificate list as sent by the server: it only consists of
+certificates the server has sent (in the order the server has sent them). It is
+B<not> a verified chain.
=item B<-prexit>
1a2b3c4d.
This option must be provided in order to use a PSK cipher.
+=item B<-psk_session file>
+
+Use the pem encoded SSL_SESSION data stored in B<file> as the basis of a PSK.
+Note that this will only work if TLSv1.3 is negotiated.
+
=item B<-ssl3>, B<-tls1>, B<-tls1_1>, B<-tls1_2>, B<-tls1_3>, B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2>, B<-no_tls1_3>
These options require or disable the use of the specified SSL or TLS protocols.
version.
When a specific TLS version is required, only that version will be offered to
and accepted from the server.
+Note that not all protocols and flags may be available, depending on how
+OpenSSL was built.
=item B<-dtls>, B<-dtls1>, B<-dtls1_2>
conjunction with B<-dtls>, B<-dtls1> or B<-dtls1_2>. This option is only
available where OpenSSL has support for SCTP enabled.
+=item B<-sctp_label_bug>
+
+Use the incorrect behaviour of older OpenSSL implementations when computing
+endpoint-pair shared secrets for DTLS/SCTP. This allows communication with
+older broken implementations but breaks interoperability with correct
+implementations. Must be used in conjunction with B<-sctp>. This option is only
+available where OpenSSL has support for SCTP enabled.
+
=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
+There are several known bugs in SSL and TLS implementations. Adding this
option enables various workarounds.
=item B<-comp>
=item B<-curves curvelist>
Specifies the list of supported curves to be sent by the client. The curve is
-is ultimately selected by the server. For a list of all curves, use:
+ultimately selected by the server. For a list of all curves, use:
$ openssl ecparam -list_curves
=item B<-cipher cipherlist>
-This allows the cipher list sent by the client to be modified. Although
-the server determines which cipher suite is used it should take the first
-supported cipher in the list sent by the client. See the B<ciphers>
-command for more information.
+This allows the TLSv1.2 and below cipher list sent by the client to be modified.
+This list will be combined with any TLSv1.3 ciphersuites that have been
+configured. Although the server determines which ciphersuite is used it should
+take the first supported cipher in the list sent by the client. See the
+B<ciphers> command for more information.
+
+=item B<-ciphersuites val>
+
+This allows the TLSv1.3 ciphersuites sent by the client to be modified. This
+list will be combined with any TLSv1.2 and below ciphersuites that have been
+configured. Although the server determines which cipher suite is used it should
+take the first supported cipher in the list sent by the client. See the
+B<ciphers> command for more information. The format for this list is a simple
+colon (":") separated list of TLSv1.3 ciphersuite names.
=item B<-starttls protocol>
If this option is not specified, then the host specified with "-connect"
will be used.
+This option is an alias of the B<-name> option for "xmpp" and "xmpp-server".
+
+=item B<-name hostname>
+
+This option is used to specify hostname information for various protocols
+used with B<-starttls> option. Currently only "xmpp", "xmpp-server",
+"smtp" and "lmtp" can utilize this B<-name> option.
+
+If this option is used with "-starttls xmpp" or "-starttls xmpp-server",
+if 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.
+
+If this option is used with "-starttls lmtp" or "-starttls smtp", it specifies
+the name to use in the "LMTP LHLO" or "SMTP EHLO" message, respectively. If
+this option is not specified, then "mail.example.com" will be used.
+
=item B<-tlsextdebug>
Print out a hex dump of any TLS extensions received from the server.
thus initialising it if needed. The engine will then be set as the default
for all available algorithms.
-=item B<-rand file(s)>
+=item B<-rand file...>
A file or files containing random data used to seed the random number
-generator, or an EGD socket (see L<RAND_egd(3)>).
+generator.
Multiple files can be specified separated by an OS-dependent character.
The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
all others.
+=item [B<-writerand file>]
+
+Writes random data to the specified I<file> upon exit.
+This can be used with a subsequent B<-rand> flag.
+
=item B<-serverinfo types>
A list of comma-separated TLS Extension Types (numbers between 0 and
after receiving ServerHello with a list of server supported protocols.
The flag B<-nextprotoneg> cannot be specified if B<-tls1_3> is used.
-=item B<-ct|noct>
+=item B<-ct>, B<-noct>
Use one of these two options to control whether Certificate Transparency (CT)
is enabled (B<-ct>) or disabled (B<-noct>).
to the server. This will only work with resumed sessions that support early
data and when the server accepts the early data.
+=item B<-enable_pha>
+
+For TLSv1.3 only, send the Post-Handshake Authentication extension. This will
+happen whether or not a certificate has been provided via B<-cert>.
+
=item B<[target]>
Rather than providing B<-connect>, the target hostname and optional port may
If a connection is established with an SSL server then any data received
from the server is displayed and any key presses will be sent to the
-server. When used interactively (which means neither B<-quiet> nor B<-ign_eof>
-have been given), the session will be renegotiated if the line begins with an
-B<R>, and if the line begins with a B<Q> or if end of file is reached, the
-connection will be closed down.
+server. If end of file is reached then the connection will be closed down. When
+used interactively (which means neither B<-quiet> nor B<-ign_eof> have been
+given), then certain commands are also recognized which perform special
+operations. These commands are a letter which must appear at the start of a
+line. They are listed below.
+
+=over 4
+
+=item B<Q>
+
+End the current SSL connection and exit.
+
+=item B<R>
+
+Renegotiate the SSL session (TLSv1.2 and below only).
+
+=item B<k>
+
+Send a key update message to the server (TLSv1.3 only)
+
+=item B<K>
+
+Send a key update message to the server and request one back (TLSv1.3 only)
+
+=back
=head1 NOTES
on the command line is no guarantee that the certificate works.
If there are problems verifying a server certificate then the
-B<-showcerts> option can be used to show the whole chain.
+B<-showcerts> option can be used to show all the certificates sent by the
+server.
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
attack. This behaviour can be changed by with the B<-verify_return_error>
option: any verify errors are then returned aborting the handshake.
+The B<-bind> option may be useful if the server or a firewall requires
+connections to come from some particular address and or port.
+
=head1 BUGS
Because this program has a lot of options and also because some of the
=head1 SEE ALSO
L<SSL_CONF_cmd(3)>, L<sess_id(1)>, L<s_server(1)>, L<ciphers(1)>,
-L<SSL_CTX_set_max_send_fragment(3)>, L<SSL_CTX_set_split_send_fragment(3)>
+L<SSL_CTX_set_max_send_fragment(3)>, L<SSL_CTX_set_split_send_fragment(3)>,
L<SSL_CTX_set_max_pipelines(3)>
=head1 HISTORY
-The -no_alt_chains options was first added to OpenSSL 1.1.0.
+The B<-no_alt_chains> option was added in OpenSSL 1.1.0.
+The B<-name> option was added in OpenSSL 1.1.1.
=head1 COPYRIGHT
-Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
-Licensed under the OpenSSL license (the "License"). You may not use
+Licensed under the Apache License 2.0 (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.
projects / openssl.git / blobdiff