S_SERVER 1 2008-05-09 0.9.9-dev OpenSSL
NAME
s_server - SSL/TLS server program
LIBRARY
libcrypto, -lcrypto
SYNOPSIS
ooppeennssssll ss__sseerrvveerr
[--aacccceepptt ppoorrtt]
[--ccoonntteexxtt iidd]
[--vveerriiffyy ddeepptthh]
[--VVeerriiffyy ddeepptthh]
[--cceerrtt ffiilleennaammee]
[--cceerrttffoorrmm DDEERR||PPEEMM]
[--kkeeyy kkeeyyffiillee]
[--kkeeyyffoorrmm DDEERR||PPEEMM]
[--ppaassss aarrgg]
[--ddcceerrtt ffiilleennaammee]
[--ddcceerrttffoorrmm DDEERR||PPEEMM]
[--ddkkeeyy kkeeyyffiillee]
[--ddkkeeyyffoorrmm DDEERR||PPEEMM]
[--ddppaassss aarrgg]
[--ddhhppaarraamm ffiilleennaammee]
[--nnbbiioo]
[--nnbbiioo__tteesstt]
[--ccrrllff]
[--ddeebbuugg]
[--mmssgg]
[--ssttaattee]
[--CCAAppaatthh ddiirreeccttoorryy]
[--CCAAffiillee ffiilleennaammee]
[--nnoocceerrtt]
[--cciipphheerr cciipphheerrlliisstt]
[--qquuiieett]
[--nnoo__ttmmpp__rrssaa]
[--ssssll22]
[--ssssll33]
[--ttllss11]
[--nnoo__ssssll22]
[--nnoo__ssssll33]
[--nnoo__ttllss11]
[--nnoo__ddhhee]
[--bbuuggss]
[--hhaacckk]
[--wwwwww]
[--WWWWWW]
[--HHTTTTPP]
[--eennggiinnee iidd]
[--ttllsseexxttddeebbuugg]
[--nnoo__ttiicckkeett]
[--iidd__pprreeffiixx aarrgg]
[--rraanndd ffiillee((ss))]
DESCRIPTION
The ss__sseerrvveerr command implements a generic SSL/TLS server which listens
for connections on a given port using SSL/TLS.
OPTIONS
-
--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.
-
--cceerrttffoorrmm ffoorrmmaatt
The certificate format to use: DER or PEM. PEM is the default.
-
-
--kkeeyy kkeeyyffiillee
The private key to use. If not specified then the certificate file will
-
be used.
-
--kkeeyyffoorrmm ffoorrmmaatt
The private format to use: DER or PEM. PEM is the default.
-
-
--ppaassss aarrgg
the private key password source. For more information about the format of aarrgg
-
see the PPAASSSS PPHHRRAASSEE AARRGGUUMMEENNTTSS section in _o_p_e_n_s_s_l(1).
-
--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.
-
--ddcceerrttffoorrmm ffoorrmmaatt, --ddkkeeyyffoorrmm ffoorrmmaatt, --ddppaassss aarrgg
addtional certificate and private key format and passphrase respectively.
-
-
--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 s_server program will be used.
-
--nnoo__ddhhee
if this option is set then no DH parameters will be loaded effectively
-
disabling the ephemeral DH cipher suites.
-
--nnoo__ttmmpp__rrssaa
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.
-
-
--nnbbiioo__tteesstt
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.
-
-
--ppsskk__hhiinntt hhiinntt
Use the PSK identity hint hhiinntt when using a PSK cipher suite.
-
-
--ppsskk kkeeyy
Use the PSK key kkeeyy when using a PSK cipher suite. The key is
-
given as a hexadecimal number without leading 0x, for example -psk
1a2b3c4d.
-
--ssssll22, --ssssll33, --ttllss11, --nnoo__ssssll22, --nnoo__ssssll33, --nnoo__ttllss11
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.
-
--ttllsseexxttddeebbuugg
print out a hex dump of any TLS extensions received from the server.
-
-
--nnoo__ttiicckkeett
disable RFC4507bis session ticket support.
-
-
--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 ss__sseerrvveerr
-
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.
-
--iidd__pprreeffiixx 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 _R_A_N_D___e_g_d(3)).
Multiple files can be specified separated by a OS-dependent character.
The separator is ;; for MS-Windows, ,, for OpenVMS, and :: for
all others.
CONNECTED COMMANDS
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.
-
NOTES
ss__sseerrvveerr can be used to debug SSL clients. To accept connections from
a web browser the command:
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 sseessss__iidd 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 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 ss__sseerrvveerr program to print out details of any
unknown cipher suites a client says it supports.
SEE ALSO
_o_p_e_n_s_s_l___s_e_s_s___i_d(1), _o_p_e_n_s_s_l___s___c_l_i_e_n_t(1), _o_p_e_n_s_s_l___c_i_p_h_e_r_s(1)