dhcpclient(1M)															    dhcpclient(1M)

NAME

       dhcpclient - Client for Dynamic Host Configuration Protocol Server

SYNOPSIS

       hostname] tracefile] class-id] debug_level] server_ipaddress] log_type] send_attempts] time_to_wait]

       interface server_ipaddress]

       hostname] tracefile] debug_level] interface server_ipaddress] log_type] time_to_wait]

       tracefile] debug_level] interface server_ipaddress] log_type]

DESCRIPTION

       is  used  to  obtain  the  configuration parameters from the Dynamic Host Configuration Protocol server (bootpd(1M)) to configure the host.
       Currently, supports 10bt(10BaseT) and 100bt(100BaseT) networks only. It does not support networks.

       is invoked by the script (see auto_parms(1M)) at boot up.  The file is used for the configuration of the interfaces. To	invoke	using  the
       script, set the variable to a non-zero value in the file.  can also be invoked at the command prompt, when the interface is not configured.

       Once  the obtains the configuration parameters from the server, it is stored in a configuration file named The configuration parameters are
       valid for a fixed time, lease time.

       The configuration information in file will be of the following format.

       The length field denotes the length of the data field following it.

       All these lines collectively indicate one record. The configuration file will have series of records.

       Since this file contains all the configuration information, it can be used to identify the server from which the  configuration	parameters
       were  obtained.	The  configuration  file  can  also  be  used to obtain the same configuration parameters from the server. So, once the is
       invoked, it will try to read the configuration file,

       While trying to read the file, the following conditions are possible:

       1.  It may be possible that the configuration file had been deleted or it may not be available for reading.

       2.  The file may have got corrupted and contains irrelevant data for the particular interface.

       3.  There may be no configuration information for the particular interface.

       4.  User may have specified option meaning that a new lease is needed.

       For all of the above cases, has to first find the server which is ready for the service. For this purpose, it will send a message.  If  the
       user  has  specified  server_ipaddress  using the option, then replies only from the specified server will be accepted.	The server in turn
       will reply with the configuration parameters that it can offer.	This message is called If the client has sent the  to  broadcast  address,
       then  it will receive from more than one server. The selects one of the obtained. Then, it will send to the server, requesting the configu-
       ration parameters. The server will reply with a positive acknowledgement called if it is willing to send the  configuration  parameters	to
       the host and with a negative acknowledgement, if it is not willing to do so. If the has received it will copy all the configuration parame-
       ters to the configuration file, else, it will send another message and repeat the whole process. This process is called	"Obtaining  a  new
       lease".

       If  all	the above 4 cases are not true, then the can directly send the message and obtain the configuration parameters as mentioned above.
       This process is called "Renewing the lease".

       The various options supported by are as described below.

   Options
       When this option is used, the client will accept the reply from the
		    server only if the in the request and reply packet matches.

       This option is used to send a hostname. The
		    hostname should be specified as an ASCII string.

       This option is used during bootup time to obtain a new lease.
		    If the client is trying to obtain the configuration parameters from the server for the first time, then does  not  exist.  So,
		    using this option, the client obtains a new lease for the interface specified.

       This option is used for dumping the internal data of an
		    interface. A sample dump is shown below.

       This option is used to specify the file name for the
		    debugging output.

       This option is used for specifying the
		    of the device group.  should be specified as an ASCII string.

       This option is used for logging of debug information.
		    debug_level specifies the amount of debug information logged.  The debugging messages are sent to

       This option is used for maintaining the lease. When invoked with this option,
		    the  runs as a daemon. The calculates how much time it needs to sleep before the lease needs to be renewed and then sleeps for
		    that time. When it wakes up, it extends the lease by sending the request to the server.

       This option is used for ignoring the current lease.
		    When this option is used, the current configuration information is discarded and request for a new lease is sent.

       This option is used for tracing the packets. It
		    displays the packet contents in a readable format.

       This option is used for releasing a lease. The
		    releases all the assigned configuration parameters. This is done by sending the message to the  server.  The  dhcpclient  then
		    empties the record corresponding to that interface in the configuration file,

       This option is used to specify the ip address of the
		    server  from  which  the  reply should be accepted.  server_ipaddress must be a unicast IP address specified in dotted decimal
		    form.

       If the	    log_type is a non zero value and if the debug_level is low enough for the process to detach from  the  tty	(see  syslog(3C)),
		    then, the logging goes to else it goes to This option is used when the is running as a daemon.

       This option prints the various version strings of the
		    to stdout.

       This option is used to specify the number of attempts the
		    packet should be sent before obtaining a reply.  send_attempts must be specified as an unsigned number.

       This option is used to specify the time interval between successive packet
		    retransmission.  time_to_wait will be in seconds.

EXAMPLES

       To the lease for the interface lan0 and invoke logging in the following set of commands is invoked at the command prompt:

       To trace the packet and get the debugging messages, use:

       This is an example of a file.

	       00 4 lan0
	       01 5 dhcph
	       02 0
	       03 0
	       04 0
	       05 0
	       06 4 4294967295
	       07 4 4294967295
	       08 4 0
	       09 4 0
	       10 4 1
	       11 6 8 0 9 25 a5 b1
	       12 4 192.11.22.107
	       13 4 255.255.255.0
	       14 4 0.0.0.0
	       15 0
	       16 4 192.11.22.3
	       17 4 192.11.22.3
	       18 0
	       19 0
	       20 0
	       21 4 0.0.0.0
	       22 0
	       23 0
	       24 39 63 82 53 63 35 1 5 33 4 ff ff ff ff 36 4 c0 b8
	       16 3 1 4 ff ff ff 0 c 5 64 68 63 70 68 2 4 ff ff b2 a8 ff

AUTHOR

       was developed by HP.

FILES

       configuration file.

SEE ALSO

       auto_parms(1M), bootpd(1M), bootpquery(1M), dhcptools(1M), syslog(3C).

       DARPA Internet Request For Comments: RFC1541, RFC1542, RFC1533, RFC1534, Assigned Numbers RFC.

																    dhcpclient(1M)