dhcpagent(1M)




NAME

     dhcpagent  -  Dynamic  Host  Configuration  Protocol  (DHCP)
     client daemon


SYNOPSIS

     dhcpagent [-a] [ -d n] [-f] [-v]


DESCRIPTION

     dhcpagent implements the client half  of  the  Dynamic  Host
     Configuration  Protocol  (DHCP) for machines running Solaris
     software.

     The dhcpagent daemon obtains  configuration  parameters  for
     the  client (local) machine's network interfaces from a DHCP
     server. These parameters  may  include  a  lease  on  an  IP
     address,  which  gives the client machine use of the address
     for the period of the lease, which may be infinite.  If  the
     client wishes to use the IP address for a period longer than
     the lease, it must negotiate an extension  using  DHCP.  For
     this  reason,  dhcpagent  must  run as a daemon, terminating
     only when the client machine powers down.

     The dhcpagent daemon is controlled through  ifconfig(1M)  in
     much  the same way that the init(1M) daemon is controlled by
     telinit(1M). dhcpagent may be invoked  as  a  user  process,
     albeit one requiring root privileges, but this is not neces-
     sary, as ifconfig(1M) will start it automatically.

     When invoked, dhcpagent enters  a  passive  state  while  it
     awaits  instructions  fromifconfig(1M).  When  it receives a
     command to configure an interface, it starts DHCP. Once DHCP
     is  complete, dhcpagent may be queried for the values of the
     various network parameters. In addition, if DHCP was used to
     obtain a lease on an address for an interface, the interface
     is configured and brought up. When a lease is  obtained,  it
     is  automatically  renewed as necessary. If the lease cannot
     be renewed, dhcpagent will take the interface  down  at  the
     end  of  the  lease. If the configured interface is found to
     have a  different  IP  address,  subnet  mask  or  broadcast
     address  from  those  obtained  from  DHCP, the interface is
     abandoned from DHCP control.

     In addition to DHCP, dhcpagent also supports BOOTP. See  RFC
     951,  Bootstrap  Protocol. Configuration parameters obtained
     from  a  BOOTP  server  are  treated  identically  to  those
     received  from  a  DHCP  server,  except that the IP address
     received from a BOOTP server always has an infinite lease.

     DHCP also acts as a mechanism to configure other information
     needed  by  the  client,  for  example,  the domain name and
     addresses of routers. Aside from the  IP  address,  netmask,
     broadcast  address  and  default  router, the agent does not
     directly configure the workstation, but instead  acts  as  a
     database which may be interrogated by other programs, and in
     particular by dhcpinfo(1).

     On clients with a single interface, this is quite  straight-
     forward. Clients with multiple interfaces may present diffi-
     culties, as it is possible that some information arriving on
     different interfaces may need to be merged, or may be incon-
     sistent. Furthermore, the configuration of the interfaces is
     asynchronous,  so  requests  may arrive while some or all of
     the interfaces  are  still  unconfigured.  To  handle  these
     cases,  one  interface  may  be designated as primary, which
     makes it the authoritative source for  the  values  of  DHCP
     parameters  in  the  case  where  no  specific  interface is
     requested.  See dhcpinfo(1) and ifconfig(1M) for details.

     The dhcpagent daemon can be configured to request a particu-
     lar  host  name. See the REQUEST_HOSTNAME description in the
     FILES section. When first configuring a client to request  a
     host  name,  you must perform the following steps as root to
     ensure that the full DHCP negotiation takes place:

     # pkill dhcpagent
     # rm /etc/dhcp/interface.dhc
     # reboot

  Messages
     The dhcpagent daemon writes information and  error  messages
     in five categories:

          critical
                Critical messages indicate severe conditions that
                prevent proper operation.

          errors
                Error messages are important, sometimes  unrecov-
                erable  events  due  to  resource  exhaustion and
                other unexpected failure of system calls;  ignor-
                ing errors may lead to degraded functionality.

          warnings
                Warnings indicate less severe  problems,  and  in
                most   cases,   describe   unusual  or  incorrect
                datagrams received from servers, or requests  for
                service that cannot be provided.

          informational
                Informational  messages  provide  key  pieces  of
                information  that  can  be  useful to debugging a
                DHCP configuration at a site. Informational  mes-
                sages  are generally controlled by the -v option.
                However, certain critical pieces of  information,
                such  as the IP address obtained, are always pro-
                vided.

          debug Debugging messages, which may be generated at two
                different  levels  of  verbosity,  are chiefly of
                benefit to persons having access to source  code,
                but  may be useful as well in debugging difficult
                DHCP configuration problems.  Debugging  messages
                are only generated when using the -d option.

     When dhcpagent is run without the -f  option,  all  messages
     are  sent to the system logger syslog(3C) at the appropriate
     matching priority and with a facility identifier LOG_DAEMON.
     When  dhcpagent  is run with the -f option, all messages are
     directed to standard error.


OPTIONS

     The following options are supported:

          -a    Adopt a configured interface. This option is  for
                use  with  diskless  DHCP clients. In the case of
                diskless DHCP, DHCP has already been performed on
                the  network  interface  providing  the operating
                system image prior  to  running  dhcpagent.  This
                option  instructs  the agent to take over control
                of the interface. It is  intended  primarily  for
                use in boot scripts.

                The effect of this option depends on whether  the
                interface is being adopted.

                If the interface is being adopted, the  following
                conditions apply:

                   o  dhcpagent uses the client id  specified  in
                      /chosen:<client_id>,  as  published  by the
                      PROM or as specified on a boot(1M)  command
                      line.  If  this  value  is not present, the
                      client id is  undefined.  The  DHCP  server
                      then determines what to use as a client id.
                      It is an error condition if  the  interface
                      is  an  Infiniband  interface  and the PROM
                      value is not present.
                If the interface is not being adopted:

                   o  dhcpagent  uses   the   value   stored   in
                      /etc/default/dhcpagent.  If  this  value is
                      not present, the client id is undefined. If
                      the interface is Infiniband and there is no
                      value in /etc/default/dhcpagent,  a  client
                      id  is  generated as described by the draft
                      document on DHCP over Infiniband, available
                      at:

                http://www.ietf.org

          -d n  Set debug level to n. Two levels of debugging are
                currently  available, 1 and 2; the latter is more
                verbose.

          -f    Run in the foreground instead of as a daemon pro-
                cess. When this option is used, messages are sent
                to standard error instead of to syslog(3C).

          -v    Provide verbose output useful for debugging  site
                configuration problems.


FILES

     /etc/dhcp/if.dhc
           Contains the configuration  for  interface.  The  mere
           existence  of this file does not imply that the confi-
           guration is correct, since the lease may have expired.

     /etc/default/dhcpagent
           Contains default values for  tunable  parameters.  All
           values  may be qualified with the interface they apply
           to by prepending the interface name and a period (".")
           to   the  interface  parameter  name.  The  parameters
           include:

           RELEASE_ON_SIGTERM
                 Indicates that a  RELEASE  rather  than  a  DROP
                 should  be  performed on managed interfaces when
                 the agent terminates.

           OFFER_WAIT
                 Indicates how long to wait between checking  for
                 valid OFFERs after sending a DISCOVER.

           ARP_WAIT
                 Indicates  how  long  to  wait  for  clients  to
                 respond  to an ARP request before concluding the
                 address in the ARP request is unused.

           IGNORE_FAILED_ARP
                 Specifies whether or not the agent should assume
                 an  address  is available, in the unlikely event
                 that ARP cannot be performed on that address.

           CLIENT_ID
                 Indicates the  value  that  should  be  used  to
                 uniquely identify the client to the server.

           PARAM_REQUEST_LIST
                 Specifies  a  list  of  comma-separated  integer
                 values  of  options  for  which the client would
                 like values.

           REQUEST_HOSTNAME
                 Indicates the client requests the DHCP server to
                 map  the  client's leased IP address to the host
                 name associated with the network interface  that
                 performs  DHCP on the client. The host name must
                 be specified in the /etc/hostname.interface file
                 for the relevant interface on a line of the form

                 inet hostname

                  where hostname is the host name requested.


ATTRIBUTES

     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWcsr                     |
    |_____________________________|_____________________________|
    | Interface Stability         | Evolving                    |
    |_____________________________|_____________________________|


SEE ALSO

     dhcpinfo(1),  ifconfig(1M),  init(1M),  syslog(3C),   attri-
     butes(5), dhcp(5)

     System Administration Guide: IP Services

     Croft, B. and Gilmore, J.,Bootstrap Protocol (BOOTP)RFC 951,
     Network Working Group, September 1985.

     Droms, R., Dynamic Host Configuration  Protocol,  RFC  2131,
     Network Working Group, March 1997.


NOTES

     Currently, configurations where more than one  interface  is
     attached  to the same physical network are unsupported. This
     precludes use of virtual interfaces.


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