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NAME    [Toc]    [Back]

       DHCP,  dhcp  -  Dynamic Host Configuration Protocol (DHCP)
       introductory information

DESCRIPTION    [Toc]    [Back]

       The Dynamic Host Configuration Protocol (DHCP) enables you
       to  automatically  assign  IP addresses to clients on networks
 from a pool of addresses.  The IP address assignment
       and  configuration occurs automatically whenever appropriate
 client systems (workstations and  portable  computers)
       attach to a network. The Tru64 UNIX implementation of DHCP
       is based on the JOIN product by JOIN Systems, Inc.   (JOIN
       is a trademark of JOIN Systems, Inc.)

       Using  DHCP  has  the  following  advantages: Automates IP
       address administration Provides central  configuration  of
       network  computers  Eliminates duplicate IP addresses Supports
 older style BOOTP (on clients only)

   DHCP Environment    [Toc]    [Back]
       DHCP is based on the client-server model, in which  client
       systems   request  resources  from  other  systems  called
       servers. A server is any host system or process that  provides
  a  network  service. A client is any host system or
       process that uses services from a server.

       A single host, or server, can provide more than  one  service.
  Servers are passive; they do not call clients, they
       wait for clients to call them.

       The client always initiates the DHCP request.  The  server
       answers  the  request,  subject  to  its own configuration

   DHCP Software    [Toc]    [Back]
       The DHCP software contains the following components:  Daemon
 programs that handle communications between the server
       (joind) and the client (joinc) A graphical user  interface
       program  (xjoin)  that  sets up the dynamic DHCP databases
       Configuration files that  contain  information  needed  to
       start  the  DHCP  daemons Administrative commands, such as
       programs that enable you to configure and maintain DHCP

       The following sections briefly describe these  components.
       For  additional  information,  see the Network Administration:
 Services guide and the JOIN  Server  Administrator's
       Guide.   The  latter  is provided by JOIN Systems, Inc. in
       HTML format, and it can be accessed by opening the following
 file with a web browser: /usr/doc/join/TOC.html

   DHCP Daemons    [Toc]    [Back]
       On  the  Tru64  UNIX  system,  the DHCP daemons (joind and
       joinc) reside in the /usr/sbin  directory.  The  following
       sections describe the daemons and their tasks.

   The joind Daemon    [Toc]    [Back]
       The joind DHCP server daemon performs the following tasks:
       Reads  the  /etc/bootptab  configuration  file   and   the
       /etc/join/server.pcy  policy  file.   Listens  for  client
       hosts requesting BOOTP or DHCP information.   Responds  to
       each client with an Internet address and other information
       that allows the client to boot and  configure  its  TCP/IP
       stack.   Supports  both BOOTP and DHCP requests making the
       bootpd daemon no longer necessary on the server.

   The joinc Daemon    [Toc]    [Back]
       The joinc DHCP client daemon performs the following tasks:
       Reads  the  /etc/join/client.pcy  policy file.  Starts the
       DHCP protocol  handshake  if  requested  to  configure  an
       interface.   Sends  a request to the broadcast address for
       the network or subnet.   Receives  configuration  information,
  configures  and  brings  up the interface, and then
       sleeps in the background  until  it  needs  to  renew  the
       lease.   Brings  down  the  interface if it cannot renew a

   The xjoin Graphical User Interface Program    [Toc]    [Back]
       The xjoin graphical user interface program resides in  the
       /usr/bin/X11  directory,  and enables you to configure the
       DHCP server and set up the DHCP dynamic databases.

   DHCP Configuration Files    [Toc]    [Back]
       The /etc/bootptab file contains entries for DHCP and BOOTP
       clients.  You add, delete, and modify entries in this file
       by using the xjoin program.  The entries are then used  by
       the  joind  server  daemon to configure the DHCP and BOOTP

       The following table describes additional  DHCP  configuration
 files that reside in the /etc/join directory:

       File         Function
       client.pcy   Governs the behavior of a DHCP client
       namepool     Specifies  names  for  dynamic  host name
       netmasks     Contains an entry for each  netmask  that
                    is  other  than  the  standard A, B, or C
       nets         Specifies the networks to administer with
                    the joind daemon
       server.pcy   Governs the behavior of a DHCP server

       The  client.pcy  and  server.pcy files contain information
       about remote systems contacted by DHCP, the  devices  used
       to  contact  these  systems, the times to contact the systems,
 and the level of access that remote systems can have
       to  the  local  system.  You must edit the client.pcy file
       using an editor.  You modify the server.pcy file by  using
       the xjoin program. Configuring these files is optional.

       The other files are configured by using the xjoin program.

   Database Files    [Toc]    [Back]
       Starting with DHCP Version 2.3.n, DHCP database files  are
       stored  in  a  new  format,  one that is incompatible with
       older formats.  An online document  explains  the  reasons
       behind this change, lists the files that are affected, and
       provides instructions for converting the files to the  new
       format.   The  document,  README-DB237,  and  a conversion
       utility, conv185-237, are located in the /etc/join  directory.

   Administrative Commands    [Toc]    [Back]
       The following table lists the DHCP administrative commands
       and their functions.  These commands are  used  by  joind,
       joinc,  or xjoin, and are not typically run by administrators.

       Command    Function
       bptojdb    Converts   bootptab   entries   into
                  static IP entries for JOIN databases
       checkdba   Checks the  JOIN  IP  address  lease
                  database for internal consistency
       dhcpcemu   Emulates a DHCP client
       dhcpconf   Controls  invocation  of DHCP on the
       dhcpparm   Prints client DHCP parameters
       jdbdump    Dumps fields from the  DHCP  dynamic
       jdbmod     Adds,  modifies,  or deletes data in
                  the DHCP dynamic database
       jdbreg     Registers hosts in the DHCP  dynamic
       jdpshow    Displays  the contents of a specific
                  JOIN server database
       probenis   Checks for the existence  of  a  NIS
                  server on the network
       shleases   Displays   a   client's  IP  address
       showdbs    Displays   the   contents   of   the
                  server's dynamic database
       showdhc    Displays  a  client's  configuration
       showhash   Dumps raw hash  table  contents  for
                  debugging use
       showtree   Dumps  raw  binary tree contents for
                  debugging use

RESTRICTIONS    [Toc]    [Back]

       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 be
       only one DHCP server for all the cluster members  using  a
       common database with failover.

SEE ALSO    [Toc]    [Back]

       Commands:   bptojdb(8),  checkdba(8),  dhcpcemu(8),  dhcpconf(8), dhcpparm(8),  jdbdump(8),  jdbmod(8),  jdbreg(8),
       jdbshow(8),    probenis(8),    shleases(8),    showdbs(8),
       showdhc(8), xjoin(8)

       Daemons: joinc(8), joind(8)

       Files:  bootptab(4)  client.pcy(4),   dhcptags(4),   namepool(4), netmasks(4), nets(4), server.pcy(4)

       Technical Overview, Network Administration: Services, JOIN
       Server  Administrator's  Guide   (/usr/doc/join/TOC.html),

[ Back ]
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