dhcpconf(8)						      System Manager's Manual						       dhcpconf(8)

NAME

       dhcpconf - Controller for DHCP client configuration

SYNOPSIS

       /usr/sbin/dhcpconf [-d] [-f] [-s] [-a server_ip] [-w seconds] interface start | drop | release

       /usr/sbin/dhcpconf [interface] dns | domain | gateways | hostname | nis | routes

OPTIONS

       Directs all DHCP protocol messages to the given IP address.  Currently not implemented.	Starts DHCP only if the interface is down.  Starts
       the DHCP client daemon, joinc, if not already running. This option is implied by the start command.  Instructs dhcpconf	to  wait  for  the
       time  specified	(if  positive) or forever (if negative), or until the operation completes or fails. This option is only relevant on opera-
       tions which cannot complete immediately. If the timer expires while the operation is in progress, dhcpconf exits with a failure	code,  but
       the  operation  continues.   If	the  user specifies a finite wait interval it should, for consistency, be at least equal to the sum of the
       timeout values for exponential backoff in the startup file, /etc/join/client.pcy.  This option is only relevant on the start command.  When
       an  interface  is  started,  joinc  sends  DHCP	discover  packets  using the exponential backoff and retransmission intervals given in the
       /etc/join/client.pcy file. If no reply is received at the end of this cycle, the client replies to the controller with failure.	When  this
       option  is in effect, joinc continues trying to contact a DHCP server forever, either by retrying the whole backoff cycle or using the last
       timeout value in the array. See client.pcy(4) for details.  Puts the interface specified under control of DHCP. The joinc server  commences
       the  DHCP  on  the  interface. Fine tuning of this process is provided by parameters in the startup file /etc/join/client.pcy.  Makes joinc
       take the interface down and transmit a DHCP release message to the DHCP server that the IP address assigned to the interface is	no  longer
       needed. The server is permitted to reassign the IP address to another client.  Tells the client daemon that it should relinquish control of
       the interface. The options to drop and release the interface are subtly different. Release is part of the DHCP protocol; drop is not.  Drop
       tells DHCP that its services for the interface in question are no longer required -- DHCP will not try to renew the lease on the IP address
       and if the lease should expire no action will be taken. This violates the protocol and is not recommended, except for testing.

DESCRIPTION

       The dhcpconf command and its companion joinc implement the client side of the Dynamic Host Configuration Protocol, DHCP. The  responsibili-
       ties of dhcpconf are as follows: Control invocation and termination of DHCP on the client's hardware interface(s).  Provide a mechanism for
       rendezvous with the transactions of DHCP which are proceeding asynchronously with respect to the client boot.

       All invocations of dhcpconf send instructions or requests to joinc, which is listening at a well known port number on the Internet Protocol
       loopback address. Unless the -w option is given, dhcpconf expects an immediate reply, and exits immediately with a success or failure code,
       depending upon the reply received. When the request is one which the client is unable to fulfill immediately, the reply	acknowledges  that
       the  request  has  been validated and that the client will initiate the task required. With the exception of start, which implicitly starts
       the client daemon, dhcpconf exits with a failure code if joinc is not already running. When the -w option is given, dhcpconf waits for  the
       requested  operation  either  to  complete,  fail,  or  wait  for the number of seconds specified in the following argument. When the timer
       expires, dhcpconf exits with a failure code, but the operation requested continues.

       The dhcpconf commands are divided into two groups: start,

       release, and drop initiate and terminate DHCP control of an interface. The remainder request dhcpconf to configure the host-wide parameters
       or service specified, according to DHCP supplied data. The latter do not, in general, need an interface to be specified, except in the cir-
       cumstance that different interfaces receive different configurations (See NOTES).

NOTES

       When two or more interfaces are configured by DHCP, the possibility exists that the configurations received may differ. This  is  the  norm
       for  interface  specific parameters, but for parameters that pertain to the host as a whole, questions of interpretation arise. List items,
       in particular, may differ for example, the default gateways. When configuring services, dhcpconf will not merge data from different  inter-
       faces.  Rather only a single interface is consulted, which, unless given on the command line, is the first one in dhcpconf program's inter-
       nal array, which is configured when the request is made.

RESTRICTIONS

       A cluster member should never be a DHCP client. It should always use static addressing.

       If a cluster is to support a DHCP server, there can only be one DHCP server for all the	cluster  members  using  a  common  database  with
       failover.

       DHCP client is not supported on dataless clients.

EXIT STATUS

       Exit codes are as follows: Success.  DHCP was not successful. The DHCP client daemon may not be running, the interface might have failed to
       configure, or no satisfactory DHCP responses were received.  Bad arguments.  A timer was set (with -w) and the interface had not configured
       before it expired.  Can only be run as root.  Some system error (should never occur)

SEE ALSO

       Commands: dhcpparm(8), joinc(8), showdhc(8), shleases(8)

       Files: client.pcy(4)

       Information: DHCP(7)

																       dhcpconf(8)