dhcp_inittab(4)
NAME
dhcp_inittab - information repository for DHCP options
DESCRIPTION
The /etc/dhcp/inittab file contains information about the
Dynamic Host Configuration Protocol (DHCP) options, which
are network configuration parameters passed from DHCP
servers to DHCP clients when a client machine uses DHCP.
Since many DHCP-related commands must parse and understand
these DHCP options, this file serves as a central location
where information about these options may be obtained.
The DHCP inittab file provides three general pieces of
information:
o A mnemonic alias, or symbol name, for each option
number. For instance, option 12 is aliased to the name
Hostname. This is useful for DHCP-related programs
that require human interaction, such as dhcpinfo(1).
o Information about the syntax for each option. This
includes information such as the type of the value,
for example, whether it is a 16-bit integer or an IP
address.
o The policy for what options are visible to which
DHCP-related programs.
The dhcp_inittab file can only be changed upon system
upgrade. Only additions of SITE options (or changes to same)
will be preserved during upgrade.
The VENDOR options defined here are intended for use by the
Solaris DHCP client and DHCP management tools. The SUNW ven-
dor space is owned by Sun, and changes are likely during
upgrade. If you need to configure the Solaris DHCP server to
support the vendor options of a different client, see
dhctab(4) for details.
Each DHCP option belongs to a certain category, which
roughly defines the scope of the option; for instance, an
option may only be understood by certain hosts within a
given site, or it may be globally understood by all DHCP
clients and servers. The following categories are defined;
the category names are not case-sensitive:
STANDARD
All client and server DHCP implementations agree on
the semantics. These are administered by the Internet
Assigned Numbers Authority (IANA). These options are
numbered from 1 to 127.
SITE Within a specific site, all client and server imple-
mentations agree on the semantics. However, at another
site the type and meaning of the option may be quite
different. These options are numbered from 128 to 254.
VENDOR
Each vendor may define 254 options unique to that ven-
dor. The vendor is identified within a DHCP packet by
the "Vendor Class" option, number 60. An option with a
specific numeric identifier belonging to one vendor
will, in general, have a type and semantics different
from that of a different vendor. Vendor options are
"super-encapsulated" into the vendor field number 43,
as defined in RFC 2132. The dhcp_inittab file only
contains Sun vendor options. Define non-Sun vendor
options in the dhcptab file.
FIELD This category allows the fixed fields within a DHCP
packet to be aliased to a mnemonic name for use with
dhcpinfo(1).
INTERNAL
This category is internal to the Solaris DHCP imple-
mentation and will not be further defined.
DHCP inittab Format
Data entries are written one per line and have seven fields;
each entry provides information for one option. Each field
is separated by a comma, except for the first and second,
which are separated by whitespace (as defined in
isspace(3C)). An entry cannot be continued onto another
line. Blank lines and those whose first non-whitespace char-
acter is '#' are ignored.
The fields, in order, are:
o Mnemonic Identifier
The Mnemonic Identifier is a user-friendly alias for the
option number; it is not case sensitive. This field must be
per-category unique and should be unique across all
categories. The option names in the STANDARD, SITE, and VEN-
DOR spaces should not overlap, or the behavior will be unde-
fined. See Mnemonic Identifiers for Options section of this
man page for descriptions of the option names.
o Category (scope)
The Category field is one of STANDARD, SITE, VENDOR, FIELD,
or INTERNAL and identifies the scope in which the option
falls.
o Option Number
The Option Number is the number of this option when it is in
a DHCP packet. This field should be per-category unique and
the STANDARD and SITE fields should not have overlapping
code fields or the behavior is undefined.
o Data Type
Data Type is one of the following values, which are
not case sensitive:
Ascii A printable character string
Bool Has no value. Scope limited to category limited
to INTERNAL. Presence of an option of this type
within a Solaris configuration file represents
TRUE, absence represents FALSE.
Octet An array of bytes
Unumber8
An 8-bit unsigned integer
Snumber8
An 8-bit signed integer
Unumber16
A 16-bit unsigned integer
Snumber16
A 16-bit signed integer
Unumber32
A 32-bit unsigned integer
Snumber32
A 32-bit signed integer
Unumber64
A 64-bit unsigned integer
Snumber64
A 64-bit signed integer
Ip An IP address
The data type field describes an indivisible unit of the
option payload, using one of the values listed above.
o Granularity
The Granularity field describes how many "indivisible units"
in the option payload make up a whole value or item for this
option. The value must be greater than zero (0) for any data
type other than Bool, in which case it must be zero (0).
o Maximum Number Of Items
This value specifies the maximum items of Granularity which
are permissible in a definition using this symbol. For exam-
ple, 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.
o Visibility
The Visibility field specifies which DHCP-related programs
make use of this information, and should always be defined
as "sdmi" for newly added options.
Mnemonic Identifiers for Options
The following table maps the mnemonic identifiers used in
Solaris DHCP to RFC 2132 options:
Symbol Code Description
Subnet 1 Subnet Mask, dotted Internet
address (IP).
UTCoffst 2 Coordinated Universal time offset
(seconds).
Router 3 List of Routers, IP.
Timeserv 4 List of RFC-868 servers, IP.
IEN116ns 5 List of IEN 116 name servers, IP.
DNSserv 6 List of DNS name servers, IP.
Logserv 7 List of MIT-LCS UDP log servers,
IP.
Cookie 8 List of RFC-865 cookie servers, IP.
Lprserv 9 List of RFC-1179 line printer
servers, IP.
Impress 10 List of Imagen Impress servers, IP.
Resource 11 List of RFC-887 resource location
servers, IP.
Hostname 12 Client's hostname, value from hosts
database.
Bootsize 13 Number of 512 octet blocks in boot
image, NUMBER.
Dumpfile 14 Path where core image should be
dumped, ASCII.
DNSdmain 15 DNS domain name, ASCII.
Swapserv 16 Client's swap server, IP.
Rootpath 17 Client's Root path, ASCII.
ExtendP 18 Extensions path, ASCII.
IpFwdF 19 IP Forwarding Enable/Disable,
NUMBER.
NLrouteF 20 Non-local Source Routing, NUMBER.
PFilter 21 Policy Filter, IP.
MaxIpSiz 22 Maximum datagram Reassembly Size,
NUMBER.
IpTTL 23 Default IP Time to Live,
(1=<x<=255), NUMBER.
PathTO 24 RFC-1191 Path MTU Aging Timeout,
NUMBER.
PathTbl 25 RFC-1191 Path MTU Plateau Table,
NUMBER.
MTU 26 Interface MTU, x>=68, NUMBER.
SameMtuF 27 All Subnets are Local, NUMBER.
Broadcst 28 Broadcast Address, IP.
MaskDscF 29 Perform Mask Discovery, NUMBER.
MaskSupF 30 Mask Supplier, NUMBER.
RDiscvyF 31 Perform Router Discovery, NUMBER.
RSolictS 32 Router Solicitation Address, IP.
StaticRt 33 Static Route, Double IP (network
router).
TrailerF 34 Trailer Encapsulation, NUMBER.
ArpTimeO 35 ARP Cache Time out, NUMBER.
EthEncap 36 Ethernet Encapsulation, NUMBER.
TcpTTL 37 TCP Default Time to Live, NUMBER.
TcpKaInt 38 TCP Keepalive Interval, NUMBER.
TcpKaGbF 39 TCP Keepalive Garbage, NUMBER.
NISdmain 40 NIS Domain name, ASCII.
NISservs 41 List of NIS servers, IP.
NTPservs 42 List of NTP servers, IP.
NetBNms 44 List of NetBIOS Name servers, IP.
NetBDsts 45 List of NetBIOS Distribution
servers, IP.
NetBNdT 46 NetBIOS Node type (1=B-node, 2=P,
4=M, 8=H).
NetBScop 47 NetBIOS scope, ASCII.
XFontSrv 48 List of X Window Font servers, IP.
XDispMgr 49 List of X Window Display managers,
IP.
LeaseTim 51 Lease Time Policy, (-1 = PERM),
NUMBER.
Message 56 Message to be displayed on client,
ASCII.
T1Time 58 Renewal (T1) time, NUMBER.
T2Time 59 Rebinding (T2) time, NUMBER.
NW_dmain 62 NetWare/IP Domain Name, ASCII.
NWIPOpts 63 NetWare/IP Options, OCTET (unknown
type).
NIS+dom 64 NIS+ Domain name, ASCII.
NIS+serv 65 NIS+ servers, IP.
TFTPsrvN 66 TFTP server hostname, ASCII.
OptBootF 67 Optional Bootfile path, ASCII.
MblIPAgt 68 Mobile IP Home Agent, IP.
SMTPserv 69 Simple Mail Transport Protocol
Server, IP.
POP3serv 70 Post Office Protocol (POP3) Server,
IP.
NNTPserv 71 Network News Transport Proto.
(NNTP) Server, IP.
WWWservs 72 Default WorldWideWeb Server, IP.
Fingersv 73 Default Finger Server, IP.
IRCservs 74 Internet Relay Chat Server, IP.
STservs 75 StreetTalk Server, IP.
STDAservs 76 StreetTalk Directory Assist.
Server, IP.
UserClas 77 User class information, ASCII.
SLP_DA 78 Directory agent, OCTET.
SLP_SS 79 Service scope, OCTET.
AgentOpt 82 Agent circuit ID, OCTET.
FQDN 89 Fully Qualified Domain Name, OCTET.
PXEarch 93 Client system architecture, NUMBER.
PXEnii 94 Client Network Device Interface,
OCTET.
PXEcid 97 UUID/GUID-based client indentifier,
OCTET.
BootFile N/A File to Boot, ASCII.
BootPath N/A Boot path prefix to apply to
client's requested boot file,
ASCII.
BootSrvA N/A Boot Server, IP.
BootSrvN N/A Boot Server Hostname, ASCII.
EchoVC N/A Echo Vendor Class Identifier Flag,
(Present=TRUE)
LeaseNeg N/A Lease is Negotiable Flag,
(Present=TRUE)
Include N/A Include listed macro values in this
macro.
EXAMPLES
Example 1: Altering the DHCP inittab File
In general, the DHCP inittab file should only be altered to
add SITE options. If other options are added, they will not
be automatically carried forward when the system is
upgraded. For instance:
ipPairs SITE, 132, IP, 2, 0, sdmi
describes an option named ipPairs, that is in the SITE
category. That is, it is defined by each individual site,
and is option code 132, which is of type IP Address, con-
sisting of a potentially infinite number of pairs of IP
addresses.
FILES
/etc/dhcp/inittab
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsr |
|_____________________________|_____________________________|
| Interface Stability | Evolving |
|_____________________________|_____________________________|
SEE ALSO
dhcpinfo(1),dhcpagent(1M), isspace(3C), dhctab(4), attri-
butes(5), dhcp(5), dhcp_modules(5)
System Administration Guide: IP Services
Alexander, S., and R. Droms. RFC 2132, DHCP Options and
BOOTP Vendor Extensions. Network Working Group. March 1997.
Droms, R. RFC 2131, Dynamic Host Configuration Protocol.
Network Working Group. March 1997.
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