=head1 SYNOPSIS
B<openssl> B<s_client>
+[B<-help>]
[B<-connect host:port>]
[B<-proxy host:port>]
[B<-servername name>]
[B<-CAfile filename>]
[B<-no-CAfile>]
[B<-no-CApath>]
+[B<-dane_tlsa_domain domain>]
+[B<-dane_tlsa_rrdata rrdata>]
[B<-attime timestamp>]
[B<-check_ss_sig>]
[B<-crl_check>]
[B<-ignore_critical>]
[B<-inhibit_any>]
[B<-inhibit_map>]
-[B<-issuer_checks>]
+[B<-no_check_time>]
[B<-partial_chain>]
[B<-policy arg>]
[B<-policy_check>]
[B<-trusted_first>]
[B<-no_alt_chains>]
[B<-use_deltas>]
+[B<-auth_level num>]
[B<-verify_depth num>]
[B<-verify_email email>]
[B<-verify_hostname hostname>]
[B<-verify_name name>]
[B<-x509_strict>]
[B<-reconnect>]
-[B<-pause>]
[B<-showcerts>]
[B<-debug>]
[B<-msg>]
[B<-quiet>]
[B<-ssl3>]
[B<-tls1>]
+[B<-tls1_1>]
+[B<-tls1_2>]
[B<-no_ssl3>]
[B<-no_tls1>]
[B<-no_tls1_1>]
[B<-no_tls1_2>]
+[B<-dtls>]
+[B<-dtls1>]
+[B<-dtls1_2>]
[B<-fallback_scsv>]
+[B<-async>]
+[B<-split_send_frag>]
+[B<-max_pipelines>]
+[B<-read_buf>]
[B<-bugs>]
+[B<-comp>]
+[B<-no_comp>]
[B<-cipher cipherlist>]
[B<-serverpref>]
[B<-starttls protocol>]
[B<-serverinfo types>]
[B<-status>]
[B<-nextprotoneg protocols>]
+[B<-ct|noct>]
+[B<-ctlogfile>]
=head1 DESCRIPTION
=over 4
+=item B<-help>
+
+Print out a usage message.
+
=item B<-connect host:port>
This specifies the host and optional port to connect to. If not specified
Do not load the trusted CA certificates from the default directory location
+=item B<-dane_tlsa_domain domain>
+
+Enable RFC6698/RFC7671 DANE TLSA authentication and specify the
+TLSA base domain which becomes the default SNI hint and the primary
+reference identifier for hostname checks. This must be used in
+combination with at least one instance of the B<-dane_tlsa_rrdata>
+option below.
+
+When DANE authentication succeeds, the diagnostic output will include
+the lowest (closest to 0) depth at which a TLSA record authenticated
+a chain certificate. When that TLSA record is a "2 1 0" trust
+anchor public key that signed (rather than matched) the top-most
+certificate of the chain, the result is reported as "TA public key
+verified". Otherwise, either the TLSA record "matched TA certificate"
+at a positive depth or else "matched EE certificate" at depth 0.
+
+=item B<-dane_tlsa_rrdata rrdata>
+
+Use one or more times to specify the RRDATA fields of the DANE TLSA
+RRset associated with the target service. The B<rrdata> value is
+specied in "presentation form", that is four whitespace separated
+fields that specify the usage, selector, matching type and associated
+data, with the last of these encoded in hexadecimal. Optional
+whitespace is ignored in the associated data field. For example:
+
+ $ openssl s_client -brief -starttls smtp \
+ -connect smtp.example.com:25 \
+ -dane_tlsa_domain smtp.example.com \
+ -dane_tlsa_rrdata "2 1 1
+ B111DD8A1C2091A89BD4FD60C57F0716CCE50FEEFF8137CDBEE0326E 02CF362B" \
+ -dane_tlsa_rrdata "2 1 1
+ 60B87575447DCBA2A36B7D11AC09FB24A9DB406FEE12D2CC90180517 616E8A18"
+ ...
+ Verification: OK
+ Verified peername: smtp.example.com
+ DANE TLSA 2 1 1 ...ee12d2cc90180517616e8a18 matched TA certificate at depth 1
+ ...
+
=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<-explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
+B<-inhibit_map>, B<-no_alt_chains>, B<-no_check_time>, 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<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-use_deltas>,
+B<-auth_level>, B<-verify_depth>, B<-verify_email>, B<-verify_hostname>,
B<-verify_ip>, B<-verify_name>, B<-x509_strict>
Set various certificate chain validation options. See the
reconnects to the same server 5 times using the same session ID, this can
be used as a test that session caching is working.
-=item B<-pause>
-
-pauses 1 second between each read and write call.
-
=item B<-showcerts>
display the whole server certificate chain: normally only the server
given as a hexadecimal number without leading 0x, for example -psk
1a2b3c4d.
-=item B<-ssl3>, B<-tls1>, B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2>
+=item B<-ssl3>, B<-tls1>, B<-tls1_1>, B<-tls1_2>, B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2>
+
+These options require or disable the use of the specified SSL or TLS protocols.
+By default B<s_client> will negotiate the highest mutually supported protocol
+version.
+When a specific TLS version is required, only that version will be offered to
+and accepted from the server.
-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 or TLS as appropriate.
+=item B<-dtls>, B<-dtls1>, B<-dtls1_2>
-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.
+These options make B<s_client> use DTLS protocols instead of TLS.
+With B<-dtls>, B<s_client> will negotiate any supported DTLS protcol version,
+whilst B<-dtls1> and B<-dtls1_2> will only support DTLS1.0 and DTLS1.2
+respectively.
=item B<-fallback_scsv>
Send TLS_FALLBACK_SCSV in the ClientHello.
+=item B<-async>
+
+switch on asynchronous mode. Cryptographic operations will be performed
+asynchronously. This will only have an effect if an asynchronous capable engine
+is also used via the B<-engine> option. For test purposes the dummy async engine
+(dasync) can be used (if available).
+
+=item B<-split_send_frag int>
+
+The size used to split data for encrypt pipelines. If more data is written in
+one go than this value then it will be split into multiple pipelines, up to the
+maximum number of pipelines defined by max_pipelines. This only has an effect if
+a suitable ciphersuite has been negotiated, an engine that supports pipelining
+has been loaded, and max_pipelines is greater than 1. See
+L<SSL_CTX_set_split_send_fragment(3)> for further information.
+
+=item B<-max_pipelines int>
+
+The maximum number of encrypt/decrypt pipelines to be used. This will only have
+an effect if an engine has been loaded that supports pipelining (e.g. the dasync
+engine) and a suiteable ciphersuite has been negotiated. The default value is 1.
+See L<SSL_CTX_set_max_pipelines(3)> for further information.
+
+=item B<-read_buf int>
+
+The default read buffer size to be used for connections. This will only have an
+effect if the buffer size is larger than the size that would otherwise be used
+and pipelining is in use (see L<SSL_CTX_set_default_read_buffer_len(3)> for
+further information).
+
=item B<-bugs>
there are several known bug in SSL and TLS implementations. Adding this
option enables various workarounds.
+=item B<-comp>
+
+Enables support for SSL/TLS compression.
+This option was introduced in OpenSSL 1.1.0.
+TLS compression is not recommended and is off by default as of
+OpenSSL 1.1.0.
+
+=item B<-no_comp>
+
+Disables support for SSL/TLS compression.
+TLS compression is not recommended and is off by default as of
+OpenSSL 1.1.0.
+
=item B<-brief>
only provide a brief summary of connection parameters instead of the
a file or files containing random data used to seed the random number
generator, or an EGD socket (see L<RAND_egd(3)>).
-Multiple files can be specified separated by a OS-dependent character.
+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.
advertise support for the TLS extension but disconnect just after
receiving ServerHello with a list of server supported protocols.
+=item B<-ct|noct>
+
+Use one of these two options to control whether Certificate Transparency (CT)
+is enabled (B<-ct>) or disabled (B<-noct>).
+If CT is enabled, signed certificate timestamps (SCTs) will be requested from
+the server and reported at handshake completion.
+
+Enabling CT also enables OCSP stapling, as this is one possible delivery method
+for SCTs.
+
+=item B<-ctlogfile>
+
+A file containing a list of known Certificate Transparency logs. See
+L<SSL_CTX_set_ctlog_list_file(3)> for the expected file format.
+
=back
=head1 CONNECTED COMMANDS
=head1 BUGS
-Because this program has a lot of options and also because some of
-the techniques used are rather old, the C source of s_client is rather
-hard to read and not a model of how things should be done. A typical
-SSL client program would be much simpler.
+Because this program has a lot of options and also because some of the
+techniques used are rather old, the C source of B<s_client> is rather hard to
+read and not a model of how things should be done.
+A typical SSL client program would be much simpler.
The B<-prexit> option is a bit of a hack. We should really report
information whenever a session is renegotiated.
projects / openssl.git / blobdiff