s_server.pod revision 325337
1 2=pod 3 4=head1 NAME 5 6openssl-s_server, 7s_server - SSL/TLS server program 8 9=head1 SYNOPSIS 10 11B<openssl> B<s_server> 12[B<-accept port>] 13[B<-context id>] 14[B<-verify depth>] 15[B<-Verify depth>] 16[B<-crl_check>] 17[B<-crl_check_all>] 18[B<-cert filename>] 19[B<-certform DER|PEM>] 20[B<-key keyfile>] 21[B<-keyform DER|PEM>] 22[B<-pass arg>] 23[B<-dcert filename>] 24[B<-dcertform DER|PEM>] 25[B<-dkey keyfile>] 26[B<-dkeyform DER|PEM>] 27[B<-dpass arg>] 28[B<-dhparam filename>] 29[B<-nbio>] 30[B<-nbio_test>] 31[B<-crlf>] 32[B<-debug>] 33[B<-msg>] 34[B<-state>] 35[B<-CApath directory>] 36[B<-CAfile filename>] 37[B<-no_alt_chains>] 38[B<-nocert>] 39[B<-client_sigalgs sigalglist>] 40[B<-named_curve curve>] 41[B<-cipher cipherlist>] 42[B<-serverpref>] 43[B<-quiet>] 44[B<-no_tmp_rsa>] 45[B<-ssl2>] 46[B<-ssl3>] 47[B<-tls1>] 48[B<-no_ssl2>] 49[B<-no_ssl3>] 50[B<-no_tls1>] 51[B<-no_dhe>] 52[B<-bugs>] 53[B<-hack>] 54[B<-www>] 55[B<-WWW>] 56[B<-HTTP>] 57[B<-engine id>] 58[B<-tlsextdebug>] 59[B<-no_ticket>] 60[B<-id_prefix arg>] 61[B<-rand file(s)>] 62[B<-serverinfo file>] 63[B<-no_resumption_on_reneg>] 64[B<-status>] 65[B<-status_verbose>] 66[B<-status_timeout nsec>] 67[B<-status_url url>] 68[B<-alpn protocols>] 69[B<-nextprotoneg protocols>] 70 71=head1 DESCRIPTION 72 73The B<s_server> command implements a generic SSL/TLS server which listens 74for connections on a given port using SSL/TLS. 75 76=head1 OPTIONS 77 78=over 4 79 80=item B<-accept port> 81 82the TCP port to listen on for connections. If not specified 4433 is used. 83 84=item B<-context id> 85 86sets the SSL context id. It can be given any string value. If this option 87is not present a default value will be used. 88 89=item B<-cert certname> 90 91The certificate to use, most servers cipher suites require the use of a 92certificate and some require a certificate with a certain public key type: 93for example the DSS cipher suites require a certificate containing a DSS 94(DSA) key. If not specified then the filename "server.pem" will be used. 95 96=item B<-certform format> 97 98The certificate format to use: DER or PEM. PEM is the default. 99 100=item B<-key keyfile> 101 102The private key to use. If not specified then the certificate file will 103be used. 104 105=item B<-keyform format> 106 107The private format to use: DER or PEM. PEM is the default. 108 109=item B<-pass arg> 110 111the private key password source. For more information about the format of B<arg> 112see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>. 113 114=item B<-dcert filename>, B<-dkey keyname> 115 116specify an additional certificate and private key, these behave in the 117same manner as the B<-cert> and B<-key> options except there is no default 118if they are not specified (no additional certificate and key is used). As 119noted above some cipher suites require a certificate containing a key of 120a certain type. Some cipher suites need a certificate carrying an RSA key 121and some a DSS (DSA) key. By using RSA and DSS certificates and keys 122a server can support clients which only support RSA or DSS cipher suites 123by using an appropriate certificate. 124 125=item B<-dcertform format>, B<-dkeyform format>, B<-dpass arg> 126 127additional certificate and private key format and passphrase respectively. 128 129=item B<-nocert> 130 131if this option is set then no certificate is used. This restricts the 132cipher suites available to the anonymous ones (currently just anonymous 133DH). 134 135=item B<-dhparam filename> 136 137the DH parameter file to use. The ephemeral DH cipher suites generate keys 138using a set of DH parameters. If not specified then an attempt is made to 139load the parameters from the server certificate file. If this fails then 140a static set of parameters hard coded into the s_server program will be used. 141 142=item B<-no_dhe> 143 144if this option is set then no DH parameters will be loaded effectively 145disabling the ephemeral DH cipher suites. 146 147=item B<-no_tmp_rsa> 148 149certain export cipher suites sometimes use a temporary RSA key, this option 150disables temporary RSA key generation. 151 152=item B<-verify depth>, B<-Verify depth> 153 154The verify depth to use. This specifies the maximum length of the 155client certificate chain and makes the server request a certificate from 156the client. With the B<-verify> option a certificate is requested but the 157client does not have to send one, with the B<-Verify> option the client 158must supply a certificate or an error occurs. 159 160If the ciphersuite cannot request a client certificate (for example an 161anonymous ciphersuite or PSK) this option has no effect. 162 163=item B<-crl_check>, B<-crl_check_all> 164 165Check the peer certificate has not been revoked by its CA. 166The CRL(s) are appended to the certificate file. With the B<-crl_check_all> 167option all CRLs of all CAs in the chain are checked. 168 169=item B<-CApath directory> 170 171The directory to use for client certificate verification. This directory 172must be in "hash format", see B<verify> for more information. These are 173also used when building the server certificate chain. 174 175=item B<-CAfile file> 176 177A file containing trusted certificates to use during client authentication 178and to use when attempting to build the server certificate chain. The list 179is also used in the list of acceptable client CAs passed to the client when 180a certificate is requested. 181 182=item B<-no_alt_chains> 183 184See the L<B<verify>|verify(1)> manual page for details. 185 186=item B<-state> 187 188prints out the SSL session states. 189 190=item B<-debug> 191 192print extensive debugging information including a hex dump of all traffic. 193 194=item B<-msg> 195 196show all protocol messages with hex dump. 197 198=item B<-nbio_test> 199 200tests non blocking I/O 201 202=item B<-nbio> 203 204turns on non blocking I/O 205 206=item B<-crlf> 207 208this option translated a line feed from the terminal into CR+LF. 209 210=item B<-quiet> 211 212inhibit printing of session and certificate information. 213 214=item B<-psk_hint hint> 215 216Use the PSK identity hint B<hint> when using a PSK cipher suite. 217 218=item B<-psk key> 219 220Use the PSK key B<key> when using a PSK cipher suite. The key is 221given as a hexadecimal number without leading 0x, for example -psk 2221a2b3c4d. 223This option must be provided in order to use a PSK cipher. 224 225=item B<-ssl2>, B<-ssl3>, B<-tls1>, B<-tls1_1>, B<-tls1_2>, B<-no_ssl2>, B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2> 226 227These options require or disable the use of the specified SSL or TLS protocols. 228By default the initial handshake uses a I<version-flexible> method which will 229negotiate the highest mutually supported protocol version. 230 231=item B<-bugs> 232 233there are several known bug in SSL and TLS implementations. Adding this 234option enables various workarounds. 235 236=item B<-hack> 237 238this option enables a further workaround for some some early Netscape 239SSL code (?). 240 241=item B<-client_sigalgs sigalglist> 242 243Signature algorithms to support for client certificate authentication 244(colon-separated list) 245 246=item B<-named_curve curve> 247 248Specifies the elliptic curve to use. NOTE: this is single curve, not a list. 249For a list of all possible curves, use: 250 251 $ openssl ecparam -list_curves 252 253=item B<-cipher cipherlist> 254 255this allows the cipher list used by the server to be modified. When 256the client sends a list of supported ciphers the first client cipher 257also included in the server list is used. Because the client specifies 258the preference order, the order of the server cipherlist irrelevant. See 259the B<ciphers> command for more information. 260 261=item B<-serverpref> 262 263use the server's cipher preferences, rather than the client's preferences. 264 265=item B<-tlsextdebug> 266 267print out a hex dump of any TLS extensions received from the server. 268 269=item B<-no_ticket> 270 271disable RFC4507bis session ticket support. 272 273=item B<-www> 274 275sends a status message back to the client when it connects. This includes 276lots of information about the ciphers used and various session parameters. 277The output is in HTML format so this option will normally be used with a 278web browser. 279 280=item B<-WWW> 281 282emulates a simple web server. Pages will be resolved relative to the 283current directory, for example if the URL https://myhost/page.html is 284requested the file ./page.html will be loaded. 285 286=item B<-HTTP> 287 288emulates a simple web server. Pages will be resolved relative to the 289current directory, for example if the URL https://myhost/page.html is 290requested the file ./page.html will be loaded. The files loaded are 291assumed to contain a complete and correct HTTP response (lines that 292are part of the HTTP response line and headers must end with CRLF). 293 294=item B<-engine id> 295 296specifying an engine (by its unique B<id> string) will cause B<s_server> 297to attempt to obtain a functional reference to the specified engine, 298thus initialising it if needed. The engine will then be set as the default 299for all available algorithms. 300 301=item B<-id_prefix arg> 302 303generate SSL/TLS session IDs prefixed by B<arg>. This is mostly useful 304for testing any SSL/TLS code (eg. proxies) that wish to deal with multiple 305servers, when each of which might be generating a unique range of session 306IDs (eg. with a certain prefix). 307 308=item B<-rand file(s)> 309 310a file or files containing random data used to seed the random number 311generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>). 312Multiple files can be specified separated by a OS-dependent character. 313The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for 314all others. 315 316=item B<-serverinfo file> 317 318a file containing one or more blocks of PEM data. Each PEM block 319must encode a TLS ServerHello extension (2 bytes type, 2 bytes length, 320followed by "length" bytes of extension data). If the client sends 321an empty TLS ClientHello extension matching the type, the corresponding 322ServerHello extension will be returned. 323 324=item B<-no_resumption_on_reneg> 325 326set SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION flag. 327 328=item B<-status> 329 330enables certificate status request support (aka OCSP stapling). 331 332=item B<-status_verbose> 333 334enables certificate status request support (aka OCSP stapling) and gives 335a verbose printout of the OCSP response. 336 337=item B<-status_timeout nsec> 338 339sets the timeout for OCSP response to B<nsec> seconds. 340 341=item B<-status_url url> 342 343sets a fallback responder URL to use if no responder URL is present in the 344server certificate. Without this option an error is returned if the server 345certificate does not contain a responder address. 346 347=item B<-alpn protocols>, B<-nextprotoneg protocols> 348 349these flags enable the 350Enable the Application-Layer Protocol Negotiation or Next Protocol 351Negotiation extension, respectively. ALPN is the IETF standard and 352replaces NPN. 353The B<protocols> list is a 354comma-separated list of supported protocol names. 355The list should contain most wanted protocols first. 356Protocol names are printable ASCII strings, for example "http/1.1" or 357"spdy/3". 358 359=back 360 361=head1 CONNECTED COMMANDS 362 363If a connection request is established with an SSL client and neither the 364B<-www> nor the B<-WWW> option has been used then normally any data received 365from the client is displayed and any key presses will be sent to the client. 366 367Certain single letter commands are also recognized which perform special 368operations: these are listed below. 369 370=over 4 371 372=item B<q> 373 374end the current SSL connection but still accept new connections. 375 376=item B<Q> 377 378end the current SSL connection and exit. 379 380=item B<r> 381 382renegotiate the SSL session. 383 384=item B<R> 385 386renegotiate the SSL session and request a client certificate. 387 388=item B<P> 389 390send some plain text down the underlying TCP connection: this should 391cause the client to disconnect due to a protocol violation. 392 393=item B<S> 394 395print out some session cache status information. 396 397=back 398 399=head1 NOTES 400 401B<s_server> can be used to debug SSL clients. To accept connections from 402a web browser the command: 403 404 openssl s_server -accept 443 -www 405 406can be used for example. 407 408Although specifying an empty list of CAs when requesting a client certificate 409is strictly speaking a protocol violation, some SSL clients interpret this to 410mean any CA is acceptable. This is useful for debugging purposes. 411 412The session parameters can printed out using the B<sess_id> program. 413 414=head1 BUGS 415 416Because this program has a lot of options and also because some of 417the techniques used are rather old, the C source of s_server is rather 418hard to read and not a model of how things should be done. A typical 419SSL server program would be much simpler. 420 421The output of common ciphers is wrong: it just gives the list of ciphers that 422OpenSSL recognizes and the client supports. 423 424There should be a way for the B<s_server> program to print out details of any 425unknown cipher suites a client says it supports. 426 427=head1 SEE ALSO 428 429L<sess_id(1)|sess_id(1)>, L<s_client(1)|s_client(1)>, L<ciphers(1)|ciphers(1)> 430 431=head1 HISTORY 432 433The -no_alt_chains options was first added to OpenSSL 1.0.2b. 434 435=cut 436