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NAME

dhcp_inittab - information repository for DHCP options
 

DESCRIPTION

The /etc/dhcp/inittab and the /etc/dhcp/inittabv6 files contain 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 and inittabv6 files provide 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.

If you make any changes to the dhcp_inittab file, note that only additions of or changes to SITE options are preserved during upgrade. For dhcp_inittabv6, no options are preserved during upgrade.

The VENDOR options defined here are intended for use by the Solaris DHCP client and DHCP management tools. The SUNW vendor 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 dhcptab(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 for IPv4 DHCP, and 1 to 65535 for DHCPv6.

SITE

Within a specific site, all client and server implementations 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 for IPv4 DHCP. DHCPv6 does not support site options.

VENDOR

Each vendor may define 254 options (65536 for DHCPv6) unique to that vendor. The vendor is identified within a DHCP packet by the "Vendor Class" option, number 60 (number 17 for DHCPv6). 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 for IPv4 DHCP, and number 17 as defined in RFC 3315 for DHCPv6. The dhcp_inittab file contains only 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 implementation and will not be further defined.

DHCP inittab and inittabv6 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 character 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 VENDOR spaces should not overlap, or the behavior will be undefined. 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. SITE is not used in inittabv6.

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

Unumber24

A 24-bit unsigned 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 IPv4 address

Ipv6

An IPv6 address

Duid

An RFC 3315 Unique Identifier

Domain

An RFC 1035-encoded domain name

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 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.

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 IPv4 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
Router
Timeserv
IEN116ns
DNSserv
Logserv
Cookie
Lprserv
Impress
Resource
Hostname
Bootsize
Dumpfile
DNSdmain
Swapserv
Rootpath
ExtendP
IpFwdF
NLrouteF
PFilter
MaxIpSiz
IpTTL
PathTO
PathTbl
MTU
SameMtuF
Broadcst
MaskDscF
MaskSupF
RDiscvyF
RSolictS
StaticRt
TrailerF
ArpTimeO
EthEncap
TcpTTL
TcpKaInt
TcpKaGbF
NISdmain
NISservs
NTPservs
NetBNms
NetBDsts
NetBNdT
NetBScop
XFontSrv
XDispMgr
LeaseTim
Message
T1Time
T2Time
NW_dmain
NWIPOpts
NIS+dom
NIS+serv
TFTPsrvN
OptBootF
MblIPAgt
SMTPserv
POP3serv
NNTPserv
WWWservs
Fingersv
IRCservs
STservs
STDAservs
UserClas
SLP_DA
SLP_SS
AgentOpt
FQDN
PXEarch
BootFile
BootPath
BootSrvA
BootSrvN
EchoVC
LeaseNeg

Mnemonic Identifiers for IPv6 Options

The following table maps the mnemonic identifiers used in Solaris DHCP to RFC 3315, 3319, 3646, 3898, 4075, and 4280 options:

Symbol	Code	Description
ClientID	1	Unique identifier for client, DUID
ServerID
Preference
Unicast
UserClass
VendorClass
SIPNames
SIPAddresses
DNSAddresses
DNSSearch
NISServers
NIS+Servers
NISDomain
NIS+Domain
SNTPServers
InfoRefresh
BCMCDomain
BCMCAddresses

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, consisting of a potentially infinite number of pairs of IP addresses.

FILES

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE Availability SUNWcsr Interface Stability

SEE ALSO

dhcpinfo(1),dhcpagent(1M), isspace(3C), dhcptab(4), attributes(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.

Droms, R. RFC 3315, Dynamic Host Configuration Protocol for IPv6 (DHCPv6). Cisco Systems. July 2003.

Schulzrinne, H., and B. Volz. RFC 3319, Dynamic Host Configuration Protocol (DHCPv6) Options for Session Initiation Protocol (SIP) Servers. Columbia University and Ericsson. July 2003.

Droms, R. RFC 3646, DNS Configuration options for Dynamic Host Configuration Protocol for IPv6 (DHCPv6). Cisco Systems. December 2003.

Kalusivalingam, V. RFC 3898, Network Information Service (NIS) Configuration Options for Dynamic Host Configuration Protocol for IPv6 (DHCPv6). Cisco Systems. October 2004.

Chowdhury, K., P. Yegani, and L. Madour. RFC 4280, Dynamic Host Configuration Protocol (DHCP) Options for Broadcast and Multicast Control Servers. Starent Networks, Cisco Systems, and Ericsson. November 2005.

Mockapetris, P.V. RFC 1035, Domain names - implementation and specification. ISI. November 1987.

Index

NAME

DESCRIPTION

DHCP inittab and inittabv6 Format

Mnemonic Identifiers for IPv4 Options

Mnemonic Identifiers for IPv6 Options

EXAMPLES

FILES

ATTRIBUTES

SEE ALSO

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