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File Formats                                           dhcptab(4)



NAME
     dhcptab - DHCP configuration parameter table

DESCRIPTION
     The dhcptab configuration table allows  network  administra-
     tors to organize 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 descrip-
     tion 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  maintain  it. However, any dhcptab must contain the fol-
     lowing 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  char-
           acters,  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 definition.  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
           symbol can be used in macro definitions.





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File Formats                                           dhcptab(4)



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

     Context
           This field defines the context  in  which  the  symbol
           definition  is to be used. It can have one of the fol-
           lowing 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 arguments which identify the client class
                 that this vendor option is associated with. Mul-
                 tiple  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 Ven-
                 dor 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 values 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.   Granular-
                 ity  and Miximum values have no meaning for sym-
                 bols 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



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File Formats                                           dhcptab(4)



                 of 1, 2, 4, and 8 octets.

                 Valid  NUMBER  types  are:  UNUMBER8,  SNUMBER8,
                 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 granular-
           ity  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 per-
           mitted.

     The following example defines a site-specific  option  (sym-
     bol)  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).



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File Formats                                           dhcptab(4)



     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 specific IP addresses.

     Up to four macro  definitions  are  consulted  by  the  DHCP
     server  to  determine  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 symbol/value pairs will  be
           selected  for  delivery  to the client. This mechanism
           permits the network administrator to select configura-
           tion  parameters  to be returned to all clients of the
           same class.

     Network
           A macro named by the dotted Internet form of the  net-
           work  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  mechan-
           ism permits the network administrator to select confi-
           guration parameters to be returned to all  clients  on
           the same network.



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File Formats                                           dhcptab(4)



     IP Address
           This macro may be named anything, but must  be  speci-
           fied  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  network  administrator  to  select  configuration
           parameters  to be returned to clients using a particu-
           lar IP address. It can also be used to deliver a macro
           defined  to  include  "server-specific" information by
           including this macro definition 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 net-
           work  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 sym-
           bol  collisions  are  replaced with those specified in
           the client identifier macro. The client mechanism per-
           mits the network administrator to select configuration
           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 symbols used in Solaris DHCP.

SEE ALSO
     dhcpmgr(1M),  dhtadm(1M),   in.dhcpd(1M),   dhcp_inittab(4),
     dhcp_network(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 University, March 1997.

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



SunOS 5.9           Last change: 15 Mar 2002                    5