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dhcptab(4)                       File Formats                       dhcptab(4)



NAME
       dhcptab - DHCP configuration parameter table

DESCRIPTION
       The  dhcptab configuration table allows network administrators to orga-
       nize groups of configuration parameters as macro definitions, which can
       then  be  referenced  in  the  definition of other useful macros. These
       macros are then used by the DHCP server to return their values to  DHCP
       and BOOTP clients.

       The preferred method of managing the dhcptab is through the  use of the
       dhcpmgr(1M) or dhtadm(1M) utility. The description of  dhcptab  entries
       included  in  this  manual  page is intended for informational purposes
       only, and should not be used to manually edit entries.

       You can view the contents of the dhcptab using the DHCP manager's  tabs
       for Macros and Options, or using the dhtadm -P command.

   Syntax of dhcptab Entries
       The  format  of a dhcptab table depends on the data store used to main-
       tain it. However, any dhcptab must contain the following fields in each
       record:

       Name            This field identifies the macro or symbol record and is
                       used as a search key into the dhcptab table.  The  name
                       of  a macro or symbol must consist of ASCII characters,
                       with the length limited to 128  characters.  Names  can
                       include spaces, except at the end of the name. The name
                       is not case-sensitive.



       Type            This field specifies the type of record and is used  as
                       a  search  key  into  the dhcptab. Currently, there are
                       only two legal values for Type:


                       m               This record is a DHCP macro definition.




                       s               This record is a  DHCP  symbol  defini-
                                       tion.  It  is used to define vendor and
                                       site-specific options.



       Value           This field contains the value for the specified type of
                       record.  For  the  m  type, the value will consist of a
                       series of symbol=value pairs, separated  by  the  colon
                       (:)  character.  For the s type, the value will consist
                       of a series of fields, separated by a comma (,),  which
                       define a symbol's characteristics. Once defined, a sym-
                       bol can be used in macro definitions.



   Symbol Characteristics
       The Value field of a symbols definition contain  the  following  fields
       describing the characteristics of a symbol:

       Context         This field defines the context in which the symbol def-
                       inition is to be used. It can have one of the following
                       values:


                       Site

                           This  symbol  defines a site-specific option, codes
                           128-254.




                       Vendor=Client Class ...

                           This symbol defines a vendor-specific option, codes
                           1-254.  The Vendor context takes ASCII string argu-
                           ments which identify the  client  class  that  this
                           vendor  option  is associated with. Multiple client
                           class names can be specified,  separated  by  white
                           space.   Only  those  clients  whose  client  class
                           matches one of these values will see  this  option.
                           For  Sun  machines, the Vendor client class matches
                           the value returned by the command uname -i  on  the
                           client, with periods replacing commas.



       Code            This  field specifies the option code number associated
                       with this symbol. Valid values are  128-254  for  site-
                       specific   options,   and   1-254  for  vendor-specific
                       options.



       Type            This field defines the type of data expected as a value
                       for  this symbol, and is not case-sensitive. Legal val-
                       ues are:


                       ASCII           NVT ASCII text. Value  is  enclosed  in
                                       double-quotes  ("). Granularity setting
                                       has no effect on symbols of this  type,
                                       since  ASCII  strings  have  a  natural
                                       granularity of one (1).




                       BOOLEAN         No value is associated with  this  data
                                       type.  Presence of symbols of this type
                                       denote boolean  TRUE,  whereas  absence
                                       denotes FALSE.  Granularity and Miximum
                                       values have no meaning for  symbols  of
                                       this type.



                       IP              Dotted  decimal  form  of  an  Internet
                                       address. Multi-IP  address  granularity
                                       is supported.



                       NUMBER          An  unsigned  number  with  a supported
                                       granularity of 1, 2, 4, and 8 octets.

                                       Valid NUMBER types are: UNUMBER8, SNUM-
                                       BER8,  UNUMBER16, SNUMBER16, UNUMBER32,
                                       SNUMBER32,  UNUMBER64,  and  SNUMBER64.
                                       See dhcp_inittab(4) for details.



                       OCTET           Uninterpreted  ASCII  representation of
                                       binary data. The client  identifier  is
                                       one  example  of an OCTET string. Valid
                                       characters are 0-9, a-f, A-F. One ASCII
                                       character   represents  one  nibble  (4
                                       bits), thus two  ASCII  characters  are
                                       needed  to represent an 8 bit quantity.
                                       The granularity setting has  no  effect
                                       on  symbols  of  this type, since OCTET
                                       strings have a natural  granularity  of
                                       one (1).

                                       For  example,  to  encode a sequence of
                                       bytes with decimal values  77,  82,  5,
                                       240,  14,  the  option  value  would be
                                       encoded as 4d5205f00e.  A  macro  which
                                       supplies  a  value  for option code 78,
                                       SLP_DA, with a  0  Mandatory  byte  and
                                       Directory  Agents  at  192.168.1.5  and
                                       192.168.0.133   would  appear  in   the
                                       dhcptab as:


                                       slpparams
                                       Macro
                                       :SLP_DA=00c0a80105c0a80085:



       Granularity     This  value specifies how many objects of Type define a
                       single instance of the symbol value. For  example,  the
                       static route option is defined to be a variable list of
                       routes. Each route consists of two IP addresses, so the
                       Type is defined to be IP, and the data's granularity is
                       defined to be 2 IP  addresses.  The  granularity  field
                       affects the IP and NUMBER data types.



       Maximum         This  value  specifies the maximum items of Granularity
                       which are permissible in a definition using  this  sym-
                       bol.  For  example,  there  can  only be one IP address
                       specified for a subnet mask, so the  Maximum number  of
                       items in this case is one (1). A  Maximum value of zero
                       (0) means that a variable number of items is permitted.



       The following example defines a site-specific  option  (symbol)  called
       MystatRt,  of code 130, type IP, and granularity 2, and a Maximum of 0.
       This definition corresponds to the internal definition  of  the  static
       route option (StaticRt).


       MystatRt s Site,130,IP,2,0



       The  following  example  demonstrates  how  a  SLP Service Scope symbol
       (SLP_SS) with a scope value of happy and mandatory byte  set  to  0  is
       encoded. The first octet of the option is the Mandatory octet, which is
       set either to 0 or 1. In this example, it is set to 0 (00). The balance
       of  the  value  is  the hexidecimal ASCII code numbers representing the
       name happy, that is, 6861707079.


       SLP_SS=006861707079



   Macro Definitions
       The following example illustrates a macro defined  using  the  MystatRt
       site option symbol just defined:


       10netnis m :MystatRt=3.0.0.0 10.0.0.30:


       Macros  can be specified in the Macro field in DHCP network tables (see
       dhcp_network(4)), which will bind particular macro definitions to  spe-
       cific IP addresses.

       Up to four macro definitions are consulted by the DHCP server to deter-
       mine the options that are returned to the requesting client.

       These macros are processed in the following order:

       Client Class            A macro named using the ASCII representation of
                               the   client   class  (e.g.  SUNW.Ultra-30)  is
                               searched for in the dhcptab. If found, its sym-
                               bol/value  pairs  will be selected for delivery
                               to the client. This mechanism permits the  net-
                               work   administrator  to  select  configuration
                               parameters to be returned to all clients of the
                               same class.



       Network                 A  macro  named  by the dotted Internet form of
                               the network address  of  the  client's  network
                               (for  example, 10.0.0.0) is searched for in the
                               dhcptab. If found, its symbol/value pairs  will
                               be  combined  with  those  of  the Client Class
                               macro. If a symbol exists in both macros,  then
                               the  Network  macro  value  overrides the value
                               defined in the Client Class macro. This  mecha-
                               nism   permits  the  network  administrator  to
                               select configuration parameters to be  returned
                               to all clients on the same network.



       IP Address              This  macro  may be named anything, but must be
                               specified in the DHCP network table for the  IP
                               address   record  assigned  to  the  requesting
                               client. If this macro is found in the  dhcptab,
                               then  its  symbol/value  pairs will be combined
                               with those of the Client Class  macro  and  the
                               Network  macro. This mechanism permits the net-
                               work  administrator  to  select   configuration
                               parameters  to  be  returned to clients using a
                               particular IP address. It can also be  used  to
                               deliver a macro defined to include "server-spe-
                               cific" information by including this macro def-
                               inition in all DHCP network table entries owned
                               by a specific server.



       Client Identifier       A macro named by the  ASCII  representation  of
                               the  client's unique identifier as shown in the
                               DHCP network table  (see  dhcp_network(4)).  If
                               found,  its  symbol/value pairs are combined to
                               the sum of the Client Class,  Network,  and  IP
                               Address   macros.  Any  symbol  collisions  are
                               replaced with those  specified  in  the  client
                               identifier  macro. The client mechanism permits
                               the network administrator to select  configura-
                               tion  parameters to be returned to a particular
                               client, regardless of what network that  client
                               is connected to.



       Refer  to System Administration Guide: IP Services for more information
       about macro processing.

       Refer to the dhcp_inittab(4) man page for more information  about  sym-
       bols used in Solaris DHCP.

SEE ALSO
       dhcpmgr(1M),   dhtadm(1M),   in.dhcpd(1M),  dhcp_inittab(4),  dhcp_net-
       work(4), dhcp(5)

       System Administration Guide: IP Services

       Alexander, S., and R. Droms, DHCP Options and BOOTP Vendor  Extensions,
       RFC 2132, Silicon Graphics, Inc., Bucknell University, March 1997.

       Droms,  R.,  Interoperation  Between DHCP and BOOTP, RFC 1534, Bucknell
       University, October 1993.

       Droms, R., Dynamic Host Configuration Protocol, RFC 2131, Bucknell Uni-
       versity, March 1997.

       Wimer,  W.,  Clarifications  and Extensions for the Bootstrap Protocol,
       RFC 1542, Carnegie Mellon University, October 1993.



SunOS 5.10                        15 Mar 2002                       dhcptab(4)