s_server.pod revision 269686
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<-nocert>] 37[B<-cipher cipherlist>] 38[B<-serverpref>] 39[B<-quiet>] 40[B<-no_tmp_rsa>] 41[B<-ssl2>] 42[B<-ssl3>] 43[B<-tls1>] 44[B<-no_ssl2>] 45[B<-no_ssl3>] 46[B<-no_tls1>] 47[B<-no_dhe>] 48[B<-no_ecdhe>] 49[B<-bugs>] 50[B<-hack>] 51[B<-www>] 52[B<-WWW>] 53[B<-HTTP>] 54[B<-engine id>] 55[B<-tlsextdebug>] 56[B<-no_ticket>] 57[B<-id_prefix arg>] 58[B<-rand file(s)>] 59[B<-status>] 60[B<-status_verbose>] 61[B<-status_timeout nsec>] 62[B<-status_url url>] 63[B<-nextprotoneg protocols>] 64 65=head1 DESCRIPTION 66 67The B<s_server> command implements a generic SSL/TLS server which listens 68for connections on a given port using SSL/TLS. 69 70=head1 OPTIONS 71 72=over 4 73 74=item B<-accept port> 75 76the TCP port to listen on for connections. If not specified 4433 is used. 77 78=item B<-context id> 79 80sets the SSL context id. It can be given any string value. If this option 81is not present a default value will be used. 82 83=item B<-cert certname> 84 85The certificate to use, most servers cipher suites require the use of a 86certificate and some require a certificate with a certain public key type: 87for example the DSS cipher suites require a certificate containing a DSS 88(DSA) key. If not specified then the filename "server.pem" will be used. 89 90=item B<-certform format> 91 92The certificate format to use: DER or PEM. PEM is the default. 93 94=item B<-key keyfile> 95 96The private key to use. If not specified then the certificate file will 97be used. 98 99=item B<-keyform format> 100 101The private format to use: DER or PEM. PEM is the default. 102 103=item B<-pass arg> 104 105the private key password source. For more information about the format of B<arg> 106see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>. 107 108=item B<-dcert filename>, B<-dkey keyname> 109 110specify an additional certificate and private key, these behave in the 111same manner as the B<-cert> and B<-key> options except there is no default 112if they are not specified (no additional certificate and key is used). As 113noted above some cipher suites require a certificate containing a key of 114a certain type. Some cipher suites need a certificate carrying an RSA key 115and some a DSS (DSA) key. By using RSA and DSS certificates and keys 116a server can support clients which only support RSA or DSS cipher suites 117by using an appropriate certificate. 118 119=item B<-dcertform format>, B<-dkeyform format>, B<-dpass arg> 120 121additional certificate and private key format and passphrase respectively. 122 123=item B<-nocert> 124 125if this option is set then no certificate is used. This restricts the 126cipher suites available to the anonymous ones (currently just anonymous 127DH). 128 129=item B<-dhparam filename> 130 131the DH parameter file to use. The ephemeral DH cipher suites generate keys 132using a set of DH parameters. If not specified then an attempt is made to 133load the parameters from the server certificate file. If this fails then 134a static set of parameters hard coded into the s_server program will be used. 135 136=item B<-no_dhe> 137 138if this option is set then no DH parameters will be loaded effectively 139disabling the ephemeral DH cipher suites. 140 141=item B<-no_ecdhe> 142 143if this option is set then no ECDH parameters will be loaded effectively 144disabling the ephemeral ECDH cipher suites. 145 146=item B<-no_tmp_rsa> 147 148certain export cipher suites sometimes use a temporary RSA key, this option 149disables temporary RSA key generation. 150 151=item B<-verify depth>, B<-Verify depth> 152 153The verify depth to use. This specifies the maximum length of the 154client certificate chain and makes the server request a certificate from 155the client. With the B<-verify> option a certificate is requested but the 156client does not have to send one, with the B<-Verify> option the client 157must supply a certificate or an error occurs. 158 159If the ciphersuite cannot request a client certificate (for example an 160anonymous ciphersuite or PSK) this option has no effect. 161 162=item B<-crl_check>, B<-crl_check_all> 163 164Check the peer certificate has not been revoked by its CA. 165The CRL(s) are appended to the certificate file. With the B<-crl_check_all> 166option all CRLs of all CAs in the chain are checked. 167 168=item B<-CApath directory> 169 170The directory to use for client certificate verification. This directory 171must be in "hash format", see B<verify> for more information. These are 172also used when building the server certificate chain. 173 174=item B<-CAfile file> 175 176A file containing trusted certificates to use during client authentication 177and to use when attempting to build the server certificate chain. The list 178is also used in the list of acceptable client CAs passed to the client when 179a certificate is requested. 180 181=item B<-state> 182 183prints out the SSL session states. 184 185=item B<-debug> 186 187print extensive debugging information including a hex dump of all traffic. 188 189=item B<-msg> 190 191show all protocol messages with hex dump. 192 193=item B<-nbio_test> 194 195tests non blocking I/O 196 197=item B<-nbio> 198 199turns on non blocking I/O 200 201=item B<-crlf> 202 203this option translated a line feed from the terminal into CR+LF. 204 205=item B<-quiet> 206 207inhibit printing of session and certificate information. 208 209=item B<-psk_hint hint> 210 211Use the PSK identity hint B<hint> when using a PSK cipher suite. 212 213=item B<-psk key> 214 215Use the PSK key B<key> when using a PSK cipher suite. The key is 216given as a hexadecimal number without leading 0x, for example -psk 2171a2b3c4d. 218 219=item B<-ssl2>, B<-ssl3>, B<-tls1>, B<-no_ssl2>, B<-no_ssl3>, B<-no_tls1> 220 221these options disable the use of certain SSL or TLS protocols. By default 222the initial handshake uses a method which should be compatible with all 223servers and permit them to use SSL v3, SSL v2 or TLS as appropriate. 224 225=item B<-bugs> 226 227there are several known bug in SSL and TLS implementations. Adding this 228option enables various workarounds. 229 230=item B<-hack> 231 232this option enables a further workaround for some some early Netscape 233SSL code (?). 234 235=item B<-cipher cipherlist> 236 237this allows the cipher list used by the server to be modified. When 238the client sends a list of supported ciphers the first client cipher 239also included in the server list is used. Because the client specifies 240the preference order, the order of the server cipherlist irrelevant. See 241the B<ciphers> command for more information. 242 243=item B<-serverpref> 244 245use the server's cipher preferences, rather than the client's preferences. 246 247=item B<-tlsextdebug> 248 249print out a hex dump of any TLS extensions received from the server. 250 251=item B<-no_ticket> 252 253disable RFC4507bis session ticket support. 254 255=item B<-www> 256 257sends a status message back to the client when it connects. This includes 258lots of information about the ciphers used and various session parameters. 259The output is in HTML format so this option will normally be used with a 260web browser. 261 262=item B<-WWW> 263 264emulates a simple web server. Pages will be resolved relative to the 265current directory, for example if the URL https://myhost/page.html is 266requested the file ./page.html will be loaded. 267 268=item B<-HTTP> 269 270emulates a simple web server. Pages will be resolved relative to the 271current directory, for example if the URL https://myhost/page.html is 272requested the file ./page.html will be loaded. The files loaded are 273assumed to contain a complete and correct HTTP response (lines that 274are part of the HTTP response line and headers must end with CRLF). 275 276=item B<-engine id> 277 278specifying an engine (by its unique B<id> string) will cause B<s_server> 279to attempt to obtain a functional reference to the specified engine, 280thus initialising it if needed. The engine will then be set as the default 281for all available algorithms. 282 283=item B<-id_prefix arg> 284 285generate SSL/TLS session IDs prefixed by B<arg>. This is mostly useful 286for testing any SSL/TLS code (eg. proxies) that wish to deal with multiple 287servers, when each of which might be generating a unique range of session 288IDs (eg. with a certain prefix). 289 290=item B<-rand file(s)> 291 292a file or files containing random data used to seed the random number 293generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>). 294Multiple files can be specified separated by a OS-dependent character. 295The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for 296all others. 297 298=item B<-status> 299 300enables certificate status request support (aka OCSP stapling). 301 302=item B<-status_verbose> 303 304enables certificate status request support (aka OCSP stapling) and gives 305a verbose printout of the OCSP response. 306 307=item B<-status_timeout nsec> 308 309sets the timeout for OCSP response to B<nsec> seconds. 310 311=item B<-status_url url> 312 313sets a fallback responder URL to use if no responder URL is present in the 314server certificate. Without this option an error is returned if the server 315certificate does not contain a responder address. 316 317=item B<-nextprotoneg protocols> 318 319enable Next Protocol Negotiation TLS extension and provide a 320comma-separated list of supported protocol names. 321The list should contain most wanted protocols first. 322Protocol names are printable ASCII strings, for example "http/1.1" or 323"spdy/3". 324 325=back 326 327=head1 CONNECTED COMMANDS 328 329If a connection request is established with an SSL client and neither the 330B<-www> nor the B<-WWW> option has been used then normally any data received 331from the client is displayed and any key presses will be sent to the client. 332 333Certain single letter commands are also recognized which perform special 334operations: these are listed below. 335 336=over 4 337 338=item B<q> 339 340end the current SSL connection but still accept new connections. 341 342=item B<Q> 343 344end the current SSL connection and exit. 345 346=item B<r> 347 348renegotiate the SSL session. 349 350=item B<R> 351 352renegotiate the SSL session and request a client certificate. 353 354=item B<P> 355 356send some plain text down the underlying TCP connection: this should 357cause the client to disconnect due to a protocol violation. 358 359=item B<S> 360 361print out some session cache status information. 362 363=back 364 365=head1 NOTES 366 367B<s_server> can be used to debug SSL clients. To accept connections from 368a web browser the command: 369 370 openssl s_server -accept 443 -www 371 372can be used for example. 373 374Most web browsers (in particular Netscape and MSIE) only support RSA cipher 375suites, so they cannot connect to servers which don't use a certificate 376carrying an RSA key or a version of OpenSSL with RSA disabled. 377 378Although specifying an empty list of CAs when requesting a client certificate 379is strictly speaking a protocol violation, some SSL clients interpret this to 380mean any CA is acceptable. This is useful for debugging purposes. 381 382The session parameters can printed out using the B<sess_id> program. 383 384=head1 BUGS 385 386Because this program has a lot of options and also because some of 387the techniques used are rather old, the C source of s_server is rather 388hard to read and not a model of how things should be done. A typical 389SSL server program would be much simpler. 390 391The output of common ciphers is wrong: it just gives the list of ciphers that 392OpenSSL recognizes and the client supports. 393 394There should be a way for the B<s_server> program to print out details of any 395unknown cipher suites a client says it supports. 396 397=head1 SEE ALSO 398 399L<sess_id(1)|sess_id(1)>, L<s_client(1)|s_client(1)>, L<ciphers(1)|ciphers(1)> 400 401=cut 402