S_SERVER(1SSL)                               OpenSSL                               S_SERVER(1SSL)

       s_server - SSL/TLS server program

       openssl s_server [-accept port] [-context id] [-verify depth] [-Verify depth] [-crl_check]
       [-crl_check_all] [-cert filename] [-certform DER|PEM] [-key keyfile] [-keyform DER|PEM]
       [-pass arg] [-dcert filename] [-dcertform DER|PEM] [-dkey keyfile] [-dkeyform DER|PEM]
       [-dpass arg] [-dhparam filename] [-nbio] [-nbio_test] [-crlf] [-debug] [-msg] [-state]
       [-CApath directory] [-CAfile filename] [-no_alt_chains] [-nocert] [-cipher cipherlist]
       [-serverpref] [-quiet] [-no_tmp_rsa] [-ssl2] [-ssl3] [-tls1] [-no_ssl2] [-no_ssl3]
       [-no_tls1] [-no_dhe] [-bugs] [-hack] [-www] [-WWW] [-HTTP] [-engine id] [-tlsextdebug]
       [-no_ticket] [-id_prefix arg] [-rand file(s)] [-serverinfo file] [-no_resumption_on_reneg]
       [-status] [-status_verbose] [-status_timeout nsec] [-status_url url] [-nextprotoneg

       The s_server command implements a generic SSL/TLS server which listens for connections on
       a given port using SSL/TLS.

       -accept port
           the TCP port to listen on for connections. If not specified 4433 is used.

       -context id
           sets the SSL context id. It can be given any string value. If this option is not
           present a default value will be used.

       -cert certname
           The certificate to use, most servers cipher suites require the use of a certificate
           and some require a certificate with a certain public key type: for example the DSS
           cipher suites require a certificate containing a DSS (DSA) key. If not specified then
           the filename "server.pem" will be used.

       -certform format
           The certificate format to use: DER or PEM. PEM is the default.

       -key keyfile
           The private key to use. If not specified then the certificate file will be used.

       -keyform format
           The private format to use: DER or PEM. PEM is the default.

       -pass arg
           the private key password source. For more information about the format of arg see the
           PASS PHRASE ARGUMENTS section in openssl(1).

       -dcert filename, -dkey keyname
           specify an additional certificate and private key, these behave in the same manner as
           the -cert and -key options except there is no default if they are not specified (no
           additional certificate and key is used). As noted above some cipher suites require a
           certificate containing a key of a certain type. Some cipher suites need a certificate
           carrying an RSA key and some a DSS (DSA) key. By using RSA and DSS certificates and
           keys a server can support clients which only support RSA or DSS cipher suites by using
           an appropriate certificate.

       -dcertform format, -dkeyform format, -dpass arg
           additional certificate and private key format and passphrase respectively.

           if this option is set then no certificate is used. This restricts the cipher suites
           available to the anonymous ones (currently just anonymous DH).

       -dhparam filename
           the DH parameter file to use. The ephemeral DH cipher suites generate keys using a set
           of DH parameters. If not specified then an attempt is made to load the parameters from
           the server certificate file. If this fails then a static set of parameters hard coded
           into the s_server program will be used.

           if this option is set then no DH parameters will be loaded effectively disabling the
           ephemeral DH cipher suites.

           certain export cipher suites sometimes use a temporary RSA key, this option disables
           temporary RSA key generation.

       -verify depth, -Verify depth
           The verify depth to use. This specifies the maximum length of the client certificate
           chain and makes the server request a certificate from the client. With the -verify
           option a certificate is requested but the client does not have to send one, with the
           -Verify option the client must supply a certificate or an error occurs.

           If the ciphersuite cannot request a client certificate (for example an anonymous
           ciphersuite or PSK) this option has no effect.

       -crl_check, -crl_check_all
           Check the peer certificate has not been revoked by its CA.  The CRL(s) are appended to
           the certificate file. With the -crl_check_all option all CRLs of all CAs in the chain
           are checked.

       -CApath directory
           The directory to use for client certificate verification. This directory must be in
           "hash format", see verify for more information. These are also used when building the
           server certificate chain.

       -CAfile file
           A file containing trusted certificates to use during client authentication and to use
           when attempting to build the server certificate chain. The list is also used in the
           list of acceptable client CAs passed to the client when a certificate is requested.

           See the verify manual page for details.

           prints out the SSL session states.

           print extensive debugging information including a hex dump of all traffic.

           show all protocol messages with hex dump.

           tests non blocking I/O

           turns on non blocking I/O

           this option translated a line feed from the terminal into CR+LF.

           inhibit printing of session and certificate information.

       -psk_hint hint
           Use the PSK identity hint hint when using a PSK cipher suite.

       -psk key
           Use the PSK key key when using a PSK cipher suite. The key is given as a hexadecimal
           number without leading 0x, for example -psk 1a2b3c4d.

       -ssl2, -ssl3, -tls1, -tls1_1, -tls1_2, -no_ssl2, -no_ssl3, -no_tls1, -no_tls1_1,
           These options require or disable the use of the specified SSL or TLS protocols.  By
           default the initial handshake uses a version-flexible method which will negotiate the
           highest mutually supported protocol version.

           there are several known bug in SSL and TLS implementations. Adding this option enables
           various workarounds.

           this option enables a further workaround for some some early Netscape SSL code (?).

       -cipher cipherlist
           this allows the cipher list used by the server to be modified.  When the client sends
           a list of supported ciphers the first client cipher also included in the server list
           is used. Because the client specifies the preference order, the order of the server
           cipherlist irrelevant. See the ciphers command for more information.

           use the server's cipher preferences, rather than the client's preferences.

           print out a hex dump of any TLS extensions received from the server.

           disable RFC4507bis session ticket support.

           sends a status message back to the client when it connects. This includes lots of
           information about the ciphers used and various session parameters.  The output is in
           HTML format so this option will normally be used with a web browser.

           emulates a simple web server. Pages will be resolved relative to the current
           directory, for example if the URL https://myhost/page is requested the file
           ./page will be loaded.

           emulates a simple web server. Pages will be resolved relative to the current
           directory, for example if the URL https://myhost/page is requested the file
           ./page will be loaded. The files loaded are assumed to contain a complete and
           correct HTTP response (lines that are part of the HTTP response line and headers must
           end with CRLF).

       -engine id
           specifying an engine (by its unique id string) will cause s_server to attempt to
           obtain a functional reference to the specified engine, thus initialising it if needed.
           The engine will then be set as the default for all available algorithms.

       -id_prefix arg
           generate SSL/TLS session IDs prefixed by arg. This is mostly useful for testing any
           SSL/TLS code (eg. proxies) that wish to deal with multiple servers, when each of which
           might be generating a unique range of session IDs (eg. with a certain prefix).

       -rand file(s)
           a file or files containing random data used to seed the random number generator, or an
           EGD socket (see RAND_egd(3)).  Multiple files can be specified separated by a OS-
           dependent character.  The separator is ; for MS-Windows, , for OpenVMS, and : for all

       -serverinfo file
           a file containing one or more blocks of PEM data.  Each PEM block must encode a TLS
           ServerHello extension (2 bytes type, 2 bytes length, followed by "length" bytes of
           extension data).  If the client sends an empty TLS ClientHello extension matching the
           type, the corresponding ServerHello extension will be returned.


           enables certificate status request support (aka OCSP stapling).

           enables certificate status request support (aka OCSP stapling) and gives a verbose
           printout of the OCSP response.

       -status_timeout nsec
           sets the timeout for OCSP response to nsec seconds.

       -status_url url
           sets a fallback responder URL to use if no responder URL is present in the server
           certificate. Without this option an error is returned if the server certificate does
           not contain a responder address.

       -nextprotoneg protocols
           enable Next Protocol Negotiation TLS extension and provide a comma-separated list of
           supported protocol names.  The list should contain most wanted protocols first.
           Protocol names are printable ASCII strings, for example "http/1.1" or "spdy/3".

       If a connection request is established with an SSL client and neither the -www nor the
       -WWW option has been used then normally any data received from the client is displayed and
       any key presses will be sent to the client.

       Certain single letter commands are also recognized which perform special operations: these
       are listed below.

       q   end the current SSL connection but still accept new connections.

       Q   end the current SSL connection and exit.

       r   renegotiate the SSL session.

       R   renegotiate the SSL session and request a client certificate.

       P   send some plain text down the underlying TCP connection: this should cause the client
           to disconnect due to a protocol violation.

       S   print out some session cache status information.

       s_server can be used to debug SSL clients. To accept connections from a web browser the

        openssl s_server -accept 443 -www

       can be used for example.

       Most web browsers (in particular Netscape and MSIE) only support RSA cipher suites, so
       they cannot connect to servers which don't use a certificate carrying an RSA key or a
       version of OpenSSL with RSA disabled.

       Although specifying an empty list of CAs when requesting a client certificate is strictly
       speaking a protocol violation, some SSL clients interpret this to mean any CA is
       acceptable. This is useful for debugging purposes.

       The session parameters can printed out using the sess_id program.

       Because this program has a lot of options and also because some of the techniques used are
       rather old, the C source of s_server is rather hard to read and not a model of how things
       should be done. A typical SSL server program would be much simpler.

       The output of common ciphers is wrong: it just gives the list of ciphers that OpenSSL
       recognizes and the client supports.

       There should be a way for the s_server program to print out details of any unknown cipher
       suites a client says it supports.

       sess_id(1), s_client(1), ciphers(1)

       The -no_alt_chains options was first added to OpenSSL 1.0.2b.

1.0.2g                                      2016-03-01                             S_SERVER(1SSL)


Designed by SanjuD(@ngineerbabu)