HP-UX Reference (11i v3 07/02) - 1M System Administration Commands A-M (vol 3)
b
bootpd(1M) bootpd(1M)
Dhcptab Configuration
The configuration file /etc/dhcptab defines groups of IP addresses that to be leased out to clients. It
also specifies certain general behaviors of the server, such as whether or not to give addresses from these
groups to
bootp clients or only to DHCP clients.
The configuration file has a format similar to the
/etc/bootptab
configuration file, with a keyword fol-
lowed by one or more tag symbols. These tag symbols are separated by colons (
:). The general format is:
keyword
:tg=value: ... :tg
=value: ... :tg=value: ...
where keyword is one of four allowed (non-case-sensitive) symbols and tg is a two or more (case-sensitive)
character tag symbol. Most tags must be followed by an equals-sign and a value as above. Some can also
appear in a boolean form with no value (i.e.
:tg:).
Blank lines and lines beginning with # are ignored in the configuration file. Keyword entries are
separated from one another by newlines; a single host entry may be extended over multiple lines if each
continued line ends with a backslash (
\
). Lines may be longer than 80 characters. Tags can appear in any
order.
IP addresses must be specified in standard Internet ‘‘dot’’ notation, and can use decimal, octal, or hexade-
cimal numbers (octal numbers begin with
0, hexadecimal numbers begin with 0x or 0X). Certain tags
accept a list of one or more IP addresses (ip_address_list). When more than one IP address is listed, they
must be separated by white space.
The currently recognized keywords are:
dhcp_pool_group
This keyword is followed by tags defining a group of IP addresses to give out to clients on the
same subnet, and the characteristics of that group. In addition to the tags defined for DHCP
groups, all of the two-letter tags for bootp entries may also be used (except for ht
, the
hardware type tag,
ha, the hardware address tag, or ci, the client ID tag. Required tags are:
subnet-mask , addr-pool-start-address
, and addr-pool-last-address.
dhcp_device_group
This keyword is used to define a group of IP addresses on a subnet much like
dhcp_pool_group, but with one exception: all clients in a device group must have the same
client class (specified with tag
class-id). This allows different types of clients to receive
different parameters from the server. Required tags are: class-id, subnet-mask ,
addr-pool-start-address
, and addr-pool-last-address.
dhcp_default_client_settings
This keyword is followed by tags to be applied to all groups. These tag values can be overridden
for a specific group if that tag is defined for that specific group. This keyword simply saves one
from entering the same tag for every group. Thus most tags that may be used for
dhcp_pool_group, and
dhcp_device_group, may be used here. The tag descriptions
specify if a tag may not be used here.
dhcp_server_settings
This keyword is followed by tags that specify a few general behaviors for the dhcp server as a
whole.
The currently supported tags for
dhcp_server_settings are:
allow-subnet-selection
This boolean tag specifies that bootpd supports the subnet selection option (RFC 3011). How-
ever, a group will support the subnet selection option only when this tag is specified in that
group.
dhcpdb-write-perf=
This parameter takes a small integer (like 2 or 5) as input. If set, the write to the
/etc/dhcpdb file will be delayed by the server. This will increase performance for busy
servers. If set to a value greater than 2, the server will spawn a new process to do the writing,
which will be a considerable performance improvement.
callback-style=OLD|NEW
Callbacks are a powerful feature that allow the system administrator to customize the opera-
tion of the server. A user-supplied executable file (typically a shell script) is executed each time
one of the main server actions is performed (example: granting a lease). An argument list is
passed in with information about the individual client and the lease. The callback-style=
90 Hewlett-Packard Company − 7 − HP-UX 11i Version 3: February 2007