Manual Pages for UNIX Darwin command on man s

Manual Pages for UNIX Darwin command on man s_server

SSERVER(1) OpenSSL SSERVER(1)

NAME

sserver - SSL/TLS server program

SYNOPSIS

ooppeennssssll sssseerrvveerr [-aacccceepptt ppoorrtt] [-ccoonntteexxtt iidd] [-vveerriiffyy ddeepptthh] [-VVeerriiffyy

ddeepptthh] [-cceerrtt ffiilleennaammee] [-kkeeyy kkeeyyffiillee] [-ddcceerrtt ffiilleennaammee] [-ddkkeeyy

kkeeyyffiillee] [-ddhhppaarraamm ffiilleennaammee] [-nnbbiioo] [-nnbbiiootteesstt] [-ccrrllff] [-ddeebbuugg]

[-mmssgg] [-ssttaattee] [-CCAAppaatthh ddiirreeccttoorryy] [-CCAAffiillee ffiilleennaammee] [-nnoocceerrtt]

[-cciipphheerr cciipphheerrlliisstt] [-qquuiieett] [-nnoottmmpprrssaa] [-ssssll22] [-ssssll33] [-ttllss11]

[-nnoossssll22] [-nnoossssll33] [-nnoottllss11] [-nnooddhhee] [-bbuuggss] [-hhaacckk] [-wwwwww]

[-WWWWWW] [-HHTTTTPP] [-eennggiinnee iidd] [-iiddpprreeffiixx aarrgg] [-rraanndd ffiillee((ss))]

DESCRIPTION

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

-aacccceepptt ppoorrtt

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

-ccoonntteexxtt iidd

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

-cceerrtt cceerrttnnaammee

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.

-kkeeyy kkeeyyffiillee

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

-ddcceerrtt ffiilleennaammee, -ddkkeeyy kkeeyynnaammee

specify an additional certificate and private key, these behave in

the same manner as the -cceerrtt and -kkeeyy 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.

-nnoocceerrtt

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

-ddhhppaarraamm ffiilleennaammee

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 sserver program will be used.

-nnooddhhee

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

-nnoottmmpprrssaa

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

-vveerriiffyy ddeepptthh, -VVeerriiffyy ddeepptthh

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 -vveerriiffyy option a certificate is requested

but the client does not have to send one, with the -VVeerriiffyy option

the client must supply a certificate or an error occurs.

-CCAAppaatthh ddiirreeccttoorryy

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

-CCAAffiillee ffiillee

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.

-ssttaattee

prints out the SSL session states.

-ddeebbuugg

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

-mmssgg

show all protocol messages with hex dump.

-nnbbiiootteesstt

tests non blocking I/O

-nnbbiioo

turns on non blocking I/O

-ccrrllff

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

-qquuiieett

inhibit printing of session and certificate information.

-ssssll22, -ssssll33, -ttllss11, -nnoossssll22, -nnoossssll33, -nnoottllss11

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, SSL v2 or TLS as appropriate.

-bbuuggss

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

-hhaacckk

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

-cciipphheerr cciipphheerrlliisstt

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 cciipphheerrss command for more information.

-wwwwww

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.

-WWWWWW

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

-HHTTTTPP

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

-eennggiinnee iidd

specifying an engine (by it's unique iidd string) will cause sssseerrvveerr 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.

-iiddpprreeffiixx aarrgg

generate SSL/TLS session IDs prefixed by aarrgg. 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).

-rraanndd ffiillee((ss))

a file or files containing random data used to seed the random number generator, or an EGD socket (see RANDegd(3)). Multiple

files can be specified separated by a OS-dependent character. The

separator is ;; for MS-Windows, ,, for OpenVMS, and :: for all others.

CCOONNNNEECCTTEEDD CCOOMMMMAANNDDSS If a connection request is established with an SSL client and neither

the -wwwwww nor the -WWWWWW 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. qq end the current SSL connection but still accept new connections. QQ end the current SSL connection and exit. rr renegotiate the SSL session. RR renegotiate the SSL session and request a client certificate. PP send some plain text down the underlying TCP connection: this should cause the client to disconnect due to a protocol violation. SS print out some session cache status information. NNOOTTEESS sssseerrvveerr can be used to debug SSL clients. To accept connections from a web browser the command:

openssl sserver -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 sseessssiidd program.

BUGS

Because this program has a lot of options and also because some of the techniques used are rather old, the C source of sserver 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 sssseerrvveerr program to print out details of any unknown cipher suites a client says it supports.