s_server.pod revision 296341
1 2=pod 3 4=head1 NAME 5 6s_server - SSL/TLS server program 7 8=head1 SYNOPSIS 9 10B<openssl> B<s_server> 11[B<-accept port>] 12[B<-context id>] 13[B<-verify depth>] 14[B<-Verify depth>] 15[B<-crl_check>] 16[B<-crl_check_all>] 17[B<-cert filename>] 18[B<-certform DER|PEM>] 19[B<-key keyfile>] 20[B<-keyform DER|PEM>] 21[B<-pass arg>] 22[B<-dcert filename>] 23[B<-dcertform DER|PEM>] 24[B<-dkey keyfile>] 25[B<-dkeyform DER|PEM>] 26[B<-dpass arg>] 27[B<-dhparam filename>] 28[B<-nbio>] 29[B<-nbio_test>] 30[B<-crlf>] 31[B<-debug>] 32[B<-msg>] 33[B<-state>] 34[B<-CApath directory>] 35[B<-CAfile filename>] 36[B<-no_alt_chains>] 37[B<-nocert>] 38[B<-cipher cipherlist>] 39[B<-serverpref>] 40[B<-quiet>] 41[B<-no_tmp_rsa>] 42[B<-ssl2>] 43[B<-ssl3>] 44[B<-tls1>] 45[B<-no_ssl2>] 46[B<-no_ssl3>] 47[B<-no_tls1>] 48[B<-no_dhe>] 49[B<-no_ecdhe>] 50[B<-bugs>] 51[B<-hack>] 52[B<-www>] 53[B<-WWW>] 54[B<-HTTP>] 55[B<-engine id>] 56[B<-tlsextdebug>] 57[B<-no_ticket>] 58[B<-id_prefix arg>] 59[B<-rand file(s)>] 60[B<-status>] 61[B<-status_verbose>] 62[B<-status_timeout nsec>] 63[B<-status_url url>] 64[B<-nextprotoneg protocols>] 65 66=head1 DESCRIPTION 67 68The B<s_server> command implements a generic SSL/TLS server which listens 69for connections on a given port using SSL/TLS. 70 71=head1 OPTIONS 72 73=over 4 74 75=item B<-accept port> 76 77the TCP port to listen on for connections. If not specified 4433 is used. 78 79=item B<-context id> 80 81sets the SSL context id. It can be given any string value. If this option 82is not present a default value will be used. 83 84=item B<-cert certname> 85 86The certificate to use, most servers cipher suites require the use of a 87certificate and some require a certificate with a certain public key type: 88for example the DSS cipher suites require a certificate containing a DSS 89(DSA) key. If not specified then the filename "server.pem" will be used. 90 91=item B<-certform format> 92 93The certificate format to use: DER or PEM. PEM is the default. 94 95=item B<-key keyfile> 96 97The private key to use. If not specified then the certificate file will 98be used. 99 100=item B<-keyform format> 101 102The private format to use: DER or PEM. PEM is the default. 103 104=item B<-pass arg> 105 106the private key password source. For more information about the format of B<arg> 107see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>. 108 109=item B<-dcert filename>, B<-dkey keyname> 110 111specify an additional certificate and private key, these behave in the 112same manner as the B<-cert> and B<-key> options except there is no default 113if they are not specified (no additional certificate and key is used). As 114noted above some cipher suites require a certificate containing a key of 115a certain type. Some cipher suites need a certificate carrying an RSA key 116and some a DSS (DSA) key. By using RSA and DSS certificates and keys 117a server can support clients which only support RSA or DSS cipher suites 118by using an appropriate certificate. 119 120=item B<-dcertform format>, B<-dkeyform format>, B<-dpass arg> 121 122additional certificate and private key format and passphrase respectively. 123 124=item B<-nocert> 125 126if this option is set then no certificate is used. This restricts the 127cipher suites available to the anonymous ones (currently just anonymous 128DH). 129 130=item B<-dhparam filename> 131 132the DH parameter file to use. The ephemeral DH cipher suites generate keys 133using a set of DH parameters. If not specified then an attempt is made to 134load the parameters from the server certificate file. If this fails then 135a static set of parameters hard coded into the s_server program will be used. 136 137=item B<-no_dhe> 138 139if this option is set then no DH parameters will be loaded effectively 140disabling the ephemeral DH cipher suites. 141 142=item B<-no_ecdhe> 143 144if this option is set then no ECDH parameters will be loaded effectively 145disabling the ephemeral ECDH 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. 223 224=item B<-ssl2>, B<-ssl3>, B<-tls1>, B<-no_ssl2>, B<-no_ssl3>, B<-no_tls1> 225 226these options disable the use of certain SSL or TLS protocols. By default 227the initial handshake uses a method which should be compatible with all 228servers and permit them to use SSL v3, SSL v2 or TLS as appropriate. 229 230=item B<-bugs> 231 232there are several known bug in SSL and TLS implementations. Adding this 233option enables various workarounds. 234 235=item B<-hack> 236 237this option enables a further workaround for some some early Netscape 238SSL code (?). 239 240=item B<-cipher cipherlist> 241 242this allows the cipher list used by the server to be modified. When 243the client sends a list of supported ciphers the first client cipher 244also included in the server list is used. Because the client specifies 245the preference order, the order of the server cipherlist irrelevant. See 246the B<ciphers> command for more information. 247 248=item B<-serverpref> 249 250use the server's cipher preferences, rather than the client's preferences. 251 252=item B<-tlsextdebug> 253 254print out a hex dump of any TLS extensions received from the server. 255 256=item B<-no_ticket> 257 258disable RFC4507bis session ticket support. 259 260=item B<-www> 261 262sends a status message back to the client when it connects. This includes 263lots of information about the ciphers used and various session parameters. 264The output is in HTML format so this option will normally be used with a 265web browser. 266 267=item B<-WWW> 268 269emulates a simple web server. Pages will be resolved relative to the 270current directory, for example if the URL https://myhost/page.html is 271requested the file ./page.html will be loaded. 272 273=item B<-HTTP> 274 275emulates a simple web server. Pages will be resolved relative to the 276current directory, for example if the URL https://myhost/page.html is 277requested the file ./page.html will be loaded. The files loaded are 278assumed to contain a complete and correct HTTP response (lines that 279are part of the HTTP response line and headers must end with CRLF). 280 281=item B<-engine id> 282 283specifying an engine (by its unique B<id> string) will cause B<s_server> 284to attempt to obtain a functional reference to the specified engine, 285thus initialising it if needed. The engine will then be set as the default 286for all available algorithms. 287 288=item B<-id_prefix arg> 289 290generate SSL/TLS session IDs prefixed by B<arg>. This is mostly useful 291for testing any SSL/TLS code (eg. proxies) that wish to deal with multiple 292servers, when each of which might be generating a unique range of session 293IDs (eg. with a certain prefix). 294 295=item B<-rand file(s)> 296 297a file or files containing random data used to seed the random number 298generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>). 299Multiple files can be specified separated by a OS-dependent character. 300The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for 301all others. 302 303=item B<-status> 304 305enables certificate status request support (aka OCSP stapling). 306 307=item B<-status_verbose> 308 309enables certificate status request support (aka OCSP stapling) and gives 310a verbose printout of the OCSP response. 311 312=item B<-status_timeout nsec> 313 314sets the timeout for OCSP response to B<nsec> seconds. 315 316=item B<-status_url url> 317 318sets a fallback responder URL to use if no responder URL is present in the 319server certificate. Without this option an error is returned if the server 320certificate does not contain a responder address. 321 322=item B<-nextprotoneg protocols> 323 324enable Next Protocol Negotiation TLS extension and provide a 325comma-separated list of supported protocol names. 326The list should contain most wanted protocols first. 327Protocol names are printable ASCII strings, for example "http/1.1" or 328"spdy/3". 329 330=back 331 332=head1 CONNECTED COMMANDS 333 334If a connection request is established with an SSL client and neither the 335B<-www> nor the B<-WWW> option has been used then normally any data received 336from the client is displayed and any key presses will be sent to the client. 337 338Certain single letter commands are also recognized which perform special 339operations: these are listed below. 340 341=over 4 342 343=item B<q> 344 345end the current SSL connection but still accept new connections. 346 347=item B<Q> 348 349end the current SSL connection and exit. 350 351=item B<r> 352 353renegotiate the SSL session. 354 355=item B<R> 356 357renegotiate the SSL session and request a client certificate. 358 359=item B<P> 360 361send some plain text down the underlying TCP connection: this should 362cause the client to disconnect due to a protocol violation. 363 364=item B<S> 365 366print out some session cache status information. 367 368=back 369 370=head1 NOTES 371 372B<s_server> can be used to debug SSL clients. To accept connections from 373a web browser the command: 374 375 openssl s_server -accept 443 -www 376 377can be used for example. 378 379Most web browsers (in particular Netscape and MSIE) only support RSA cipher 380suites, so they cannot connect to servers which don't use a certificate 381carrying an RSA key or a version of OpenSSL with RSA disabled. 382 383Although specifying an empty list of CAs when requesting a client certificate 384is strictly speaking a protocol violation, some SSL clients interpret this to 385mean any CA is acceptable. This is useful for debugging purposes. 386 387The session parameters can printed out using the B<sess_id> program. 388 389=head1 BUGS 390 391Because this program has a lot of options and also because some of 392the techniques used are rather old, the C source of s_server is rather 393hard to read and not a model of how things should be done. A typical 394SSL server program would be much simpler. 395 396The output of common ciphers is wrong: it just gives the list of ciphers that 397OpenSSL recognizes and the client supports. 398 399There should be a way for the B<s_server> program to print out details of any 400unknown cipher suites a client says it supports. 401 402=head1 SEE ALSO 403 404L<sess_id(1)|sess_id(1)>, L<s_client(1)|s_client(1)>, L<ciphers(1)|ciphers(1)> 405 406=head1 HISTORY 407 408The -no_alt_chains options was first added to OpenSSL 1.0.1n and 1.0.2b. 409 410=cut 411