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 recordand is used as a search key into the dhcptab table.
The name of a macro or symbol must consist of ASCIIcharacters, with the length limited to 128 charac-
ters. Names can include spaces, except at the endof the name. The name is not case-sensitive.
Type This field specifies the type of record and is usedas 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 isused to define vendor and site-specific
options. Value This field contains the value for the specifiedtype of record. For the m type, the value will con-
sist of a series of symbol=value pairs, separatedSunOS 5.11 Last change: 15 Mar 2002 1
File Formats dhcptab(4)
by the colon (:) character. For the s type, the value will consist of a series of fields, separatedby a comma (,), which define a symbol's charac-
teristics. Once defined, a symbol can be used in macro definitions. Symbol CharacteristicsThe 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 following values: Site This symboldefines a site-
specific option,codes 128-254.
Vendor=Client Class ... This symboldefines 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. 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.SunOS 5.11 Last change: 15 Mar 2002 2
File Formats dhcptab(4)
Code This field specifies the option code number associated with this symbol. Valid values are128-254 for site-specific options, and 1-254
for vendor-specific options.
Type This field defines the type of data expectedas a value for this symbol, and is not case-
sensitive. Legal values are: ASCII NVT ASCII text. Value is enclosedin 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 Internetaddress. Multi-IP address granu-
larity is supported.NUMBER An unsigned number with a sup-
ported granularity 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 representationof binary data. The client iden-
tifier is one example of an OCTETstring. Valid characters are 0-9,
a-f, A-F. One ASCII character
represents one nibble (4 bits), thus two ASCII characters areneeded to represent an 8 bit quan-
tity. The granularity setting hasSunOS 5.11 Last change: 15 Mar 2002 3
File Formats dhcptab(4)
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 foroption 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 thedhcptab 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 ofGranularity which are permissible in a defin-
ition using this symbol. 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 (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). MystatRt s Site,130,IP,2,0SunOS 5.11 Last change: 15 Mar 2002 4
File Formats dhcptab(4)
The following example demonstrates how a SLP Service Scopesymbol (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 networktables (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 represen-
tation 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 thenetwork administrator to select confi-
guration 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 thedhcptab. 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. ThisSunOS 5.11 Last change: 15 Mar 2002 5
File Formats dhcptab(4)
mechanism permits the network adminis-
trator to select configuration parame-
ters 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. Ifthis 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. Thismechanism permits the network adminis-
trator to select configuration parame-
ters to be returned to clients using a particular IP address. It can also be used to deliver a macro defined toinclude "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 representa-
tion of the client's unique identifier as shown in the DHCP network table (seedhcp_network(4)). If found, its
symbol/value pairs are combined to the sum of the Client Class, Network, andIP Address macros. Any symbol colli-
sions are replaced with those specified in the client identifier macro. The client mechanism permits the network administrator to select configurationparameters to be returned to a particu-
lar 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)
SunOS 5.11 Last change: 15 Mar 2002 6
File Formats dhcptab(4)
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 5.11 Last change: 15 Mar 2002 7