Tribblix: manual page: dhcp

DHCP_INITTAB(5) File Formats and Configurations DHCP_INITTAB(5)

NAME

dhcp_inittab - information repository for DHCP options

DESCRIPTION

The /etc/dhcp/inittab and the /etc/dhcp/inittab6 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 inittab6 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 /etc/dhcp/inittab file, note that only
additions of or changes to SITE options are preserved during upgrade.
For /etc/dhcp/inittab6, 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(5) 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 /etc/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 inittab6 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 inittab6.

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 2 Coordinated Universal time offset
(seconds) [deprecated].
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.
ClientFQDN 81 Fully Qualified Domain Name, OCTET.
AgentOpt 82 Agent circuit ID, OCTET.
FQDN 89 Fully Qualified Domain Name, OCTET.
PXEarch 93 Client system architecture, NUMBER.
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)

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 2 Unique identifier for server, DUID
Preference 7 Server preference, NUMBER
Unicast 12 Unicast server address, IPV6
UserClass 15 User classes for client, OCTET
VendorClass 16 Vendor client hardware items, OCTET
SIPNames 21 SIP proxy server name list, DOMAIN
SIPAddresses 22 SIP proxy server addresses in
preference order, IPV6
DNSAddresses 23 DNS server addresses in preference
order, IPV6
DNSSearch 24 DNS search list, DOMAIN
NISServers 27 NIS server addresses in preference
order, IPV6
NIS+Servers 28 NIS+ server addresses in preference
order, IPV6
NISDomain 29 NIS domain name, DOMAIN
NIS+Domain 30 NIS+ domain name, DOMAIN
SNTPServers 31 IPV6
InfoRefresh 32 UNUMBER32
BCMCDomain 33 Broadcast/multicast control server
name list, DOMAIN
BCMCAddresses 34 Broadcast/multicast control server
addresses, IPV6

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

/etc/dhcp/inittab
/etc/dhcp/inittabv6