S_TIME(1) OpenSSL S_TIME(1)
NAME
s_time - SSL/TLS performance timing program
SYNOPSIS
openssl s_time [-connect host:port] [-www page] [-cert filename] [-key filename] [-CApath directory]
[-CAfile filename] [-reuse] [-new] [-verify depth] [-nbio] [-time seconds] [-ssl2] [-ssl3] [-bugs]
[-cipher cipherlist]
DESCRIPTION
The s_client command implements a generic SSL/TLS client which connects to a remote host using
SSL/TLS. It can request a page from the server and includes the time to transfer the payload data in
its timing measurements. It measures the number of connections within a given timeframe, the amount
of data transferred (if any), and calculates the average time spent for one connection.
OPTIONS
-connect host:port
This specifies the host and optional port to connect to.
-www page
This specifies the page to GET from the server. A value of '/' gets the index.htm[l] page. If
this parameter is not specified, then s_time will only perform the handshake to establish SSL
connections but not transfer any payload data.
-cert certname
The certificate to use, if one is requested by the server. The default is not to use a
certificate. The file is in PEM format.
-key keyfile
The private key to use. If not specified then the certificate file will be used. The file is in
PEM format.
-verify depth
The verify depth to use. This specifies the maximum length of the server certificate chain and
turns on server certificate verification. Currently the verify operation continues after errors
so all the problems with a certificate chain can be seen. As a side effect the connection will
never fail due to a server certificate verify failure.
-CApath directory
The directory to use for server certificate verification. This directory must be in "hash
format", see verify for more information. These are also used when building the client
certificate chain.
-CAfile file
A file containing trusted certificates to use during server authentication and to use when
attempting to build the client certificate chain.
-new
performs the timing test using a new session ID for each connection. If neither -new nor -reuse
are specified, they are both on by default and executed in sequence.
-reuse
performs the timing test using the same session ID; this can be used as a test that session
caching is working. If neither -new nor -reuse are specified, they are both on by default and
executed in sequence.
-nbio
turns on non-blocking I/O.
-ssl2, -ssl3
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. The timing program is not as rich in options to turn protocols on and off
as the s_client(1) program and may not connect to all servers.
Unfortunately there are a lot of ancient and broken servers in use which cannot handle this
technique and will fail to connect. Some servers only work if TLS is turned off with the -ssl3
option; others will only support SSL v2 and may need the -ssl2 option.
-bugs
there are several known bug in SSL and TLS implementations. Adding this option enables various
workarounds.
-cipher cipherlist
this allows the cipher list sent by the client to be modified. Although the server determines
which cipher suite is used it should take the first supported cipher in the list sent by the
client. See the ciphers(1) command for more information.
-time length
specifies how long (in seconds) s_time should establish connections and optionally transfer
payload data from a server. Server and client performance and the link speed determine how many
connections s_time can establish.
NOTES
s_client can be used to measure the performance of an SSL connection. To connect to an SSL HTTP
server and get the default page the command
openssl s_time -connect servername:443 -www / -CApath yourdir -CAfile yourfile.pem -cipher commoncipher [-ssl3]
would typically be used (https uses port 443). 'commoncipher' is a cipher to which both client and
server can agree, see the ciphers(1) command for details.
If the handshake fails then there are several possible causes, if it is nothing obvious like no
client certificate then the -bugs, -ssl2, -ssl3 options can be tried in case it is a buggy server. In
particular you should play with these options before submitting a bug report to an OpenSSL mailing
list.
A frequent problem when attempting to get client certificates working is that a web client complains
it has no certificates or gives an empty list to choose from. This is normally because the server is
not sending the clients certificate authority in its "acceptable CA list" when it requests a
certificate. By using s_client(1) the CA list can be viewed and checked. However some servers only
request client authentication after a specific URL is requested. To obtain the list in this case it
is necessary to use the -prexit option of s_client(1) and send an HTTP request for an appropriate
page.
If a certificate is specified on the command line using the -cert option it will not be used unless
the server specifically requests a client certificate. Therefor merely including a client certificate
on the command line is no guarantee that the certificate works.
BUGS
Because this program does not have all the options of the s_client(1) program to turn protocols on
and off, you may not be able to measure the performance of all protocols with all servers.
The -verify option should really exit if the server verification fails.
SEE ALSO
s_client(1), s_server(1), ciphers(1)
0.9.7l 2004-01-07 S_TIME(1)
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