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DC_SERVER(1)			   distcache			  DC_SERVER(1)

       dc_server - Distributed session cache server

       dc_server -listen <address> [options]

       dc_server runs a	cache server and starts	listening on a configurable
       network address for connections.	Incoming connections are expected to
       communicate using the distcache(8) protocol, and	would typically	be in-
       stances of dc_client(1) running on other	machines.

	   After initialising, dc_server will detach from the parent process,
	   close standard file-descriptors, etc. If this flag is not set,
	   dc_server will run in the foreground. It is recommended to use this
	   flag	in combination with the	pidfile	flag to	simplify stopping and
	   restarting services.

       -user user
	   This	switch will attempt to change user privileges of dc_server to
	   the given user ID after initialising	its listening socket. On most
	   systems, this can only work if dc_server is started as the root
	   user. It is important to note that the change of user ID occurs af-
	   ter the listening socket is create. This ensures that the listening
	   socket is created with the most restrictive permissions, and	that
	   the ability to connect to servers at	run-time corresponds to	the
	   given user (rather than having unusual root permissions on

       -listen address
	   Configures the address on which dc_server should listen for incom-
	   ing connections.  The syntax	is that	defined	by the libnal API.
	   Some	examples follow;

	       # Listen	on port	9001 for all TCP/IPv4 interfaces
	       dc_server -listen IP:9001

	       # Listen	on port	9001 on	a specific TCP/IPv4 interface
	       dc_server -listen IP:
	       dc_server -listen IP:cacheserver.localnet:9001

	       # Listen	on a unix domain socket	in the /tmp directory
	       dc_server -listen UNIX:/tmp/cacheserver

       -sockowner user
	   This	switch is only useful when listening (see -listen) on unix do-
	   main	sockets.  It will attempt to change ownership of the created
	   socket file.

       -sockgroup group
	   This	switch is only useful when listening (see -listen) on unix do-
	   main	sockets.  It will attempt to change group ownership of the
	   created socket file.

       -sockperms perms
	   This	switch is only useful when listening (see -listen) on unix do-
	   main	sockets.  It will attempt to change file permissions for the
	   created socket file,	and is specified in the	standard octal nota-
	   tion	used for unix file permissions.	Eg. to start dc_server to run
	   as the nobody user, listening on a unix domain socket that can only
	   be connected	to by the root user or members of the dcclient group;

	       # dc_server -listen UNIX:/tmp/cacheserver -user nobody \
		     -sockgroup	dcclient -sockperms 440

       -sessions num
	   Specifies a maximum number of sessions that should be stored	in the
	   cache. All sessions in a cache have an expiry time so that they
	   will, if they have not been forcibly	removed	before that time, be
	   expired out of the cache. If	it is desirable	to allow long session
	   timeouts under normal situations yet	protect	against	the session
	   cache growing without limit periods of high-load, this limit	can
	   provide the required	balance. If the	session	cache reaches this
	   limit, it will automatically	rotate out those sessions in the cache
	   that	are due	to expire soonest. It is not (yet) possible to have no
	   limit at all, though	a future version should	support	this by	allow-
	   ing the user	to specify zero.

	   The default value for this flag is 512.

       -progress num
	   dc_server will, by default, log a line of output to stdout whenever
	   there is cache activity, but	will make sure to do so	no more	often
	   than	once a second.	If -progress is	specified, this	will take
	   precedence  so that output will be emitted whenever num operations
	   have	occurred since the last	output,	irrespective of	how little
	   time	has elapsed. The once-a-second logic remains behind this, so
	   that	if less	than num operations has	taken place but	at least one
	   second has passed, output will still	be logged. This	flag has no
	   effect if -daemon is	used.

       -pidfile	path
	   This	is a standard flag for many programs, and most useful in com-
	   bination with -daemon. When -pidfile	is specified dc_server will
	   write its process ID	to a file at the specified path	upon success-
	   ful initialisation. To use this path	file to	later kill the running
	   dc_server instance, use something like (where is	what-
	   ever	path was);

	       kill `cat`

	   The default behaviour of dc_server is to silently ignore SIGUSR1
	   and SIGUSR2 signals,	but with this switch enabled it	will handle
	   these signals and close down	cleanly	(mainly	useful for developers
	   as an alternative to	SIGKILL	which is less useful for debugging
	   memory leaks).

       -h, -help, -?
	   Any of these	flags will cause dc_server to display a	brief usage
	   summary to the console and exit cleanly. Any	other flags are	ig-

	   Distributed caching client proxy.

	   Distcache protocol analyser and debugging tool.

	   Overview of the distcache architecture.
	   Distcache home page.

       This toolkit was	designed and implemented by Geoff Thorpe for Crypto-
       graphic Appliances Incorporated.	Since the project was released into
       open source, it has a home page and a project environment where devel-
       opment, mailing lists, and releases are organised. For problems with
       the software or this man	page please check for new releases at the
       project web-site	below, mail the	users mailing list described there, or
       contact the author at

       Home Page:

1.5.1				  2004.10.19			  DC_SERVER(1)


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