DHCP Files
The following table lists files associated with Solaris DHCP.
Table 12-2 Files and Tables Used by DHCP Daemons and Commands
File/Table | Description |
|---|---|
dhcptab | A generic term for the table of DHCP configuration information recorded as options with assigned values, which are then grouped into macros. The name of the dhcptab table and its location is determined by the data store you use for DHCP information. |
DHCP network table | Maps IP addresses to client IDs and configuration options. DHCP network tables are named according to the IP address of the network, such as 10.21.32.0. There is no file called dhcp_network. The name and location of DHCP network tables is determined by the data store you use for DHCP information. |
dhcpsvc.conf | Records DHCP daemon startup options and the data store resource and location of the dhcptab and network tables. The file is located in the /etc/inet directory. |
nsswitch.conf | Specifies the location of name service databases and the order in which to search them for various kinds of information. The nsswitch.conf file is consulted when you configure a DHCP server in order to obtain accurate configuration information. The file is located in the /etc directory. |
resolv.conf | Contains information used by the DNS resolver. During DHCP server configuration, this file is consulted for information about the DNS domain and DNS server. The file is located in the /etc directory. |
| dhcp.interface | Indicates that DHCP is to be used on the client's network interface specified in the file name, such as dhcp.qe0. The dhcp.interface file might contain commands that are passed as options to the ifconfig interface dhcp start option command used to start DHCP on the client. The file is located in the /etc directory on Solaris DHCP client systems. |
interface.dhc | Contains the configuration parameters obtained from DHCP for the given network interface. The client caches the current configuration information in /etc/dhcp/interface.dhc when the interface's IP address lease is dropped. The next time DHCP starts on the interface, the client requests to use the cached configuration if the lease has not expired. If the DHCP server denies the request, the client begins the standard DHCP lease negotiation process. |
dhcpagent | Sets parameter values for the dhcpagent client daemon. The path to the file is /etc/default/dhcpagent. See the file itself or the dhcpagent(1M) man page for information about the parameters. |
DHCP inittab | Defines aspects of DHCP option codes, such as the data type, and assigns mnemonic labels. See the dhcp_inittab man page for more information about the file syntax. On the client, the information in the /etc/dhcp/inittab file is used by dhcpinfo to provide more meaningful information to human readers of the information. This file replaces the /etc/dhcp/dhcptags file. "DHCP Option Information" provides more information about this replacement. On the DHCP server system, this file is used by the DHCP daemon and management tools to obtain DHCP option information. |
DHCP Option Information
Historically, DHCP option information has been stored in several places in Solaris DHCP, including the server's dhcptab table, the client's dhcptags file, and internal tables of in.dhcpd, snoop, dhcpinfo, and dhcpmgr. In an effort to consolidate option information, the Solaris 8 DHCP product introduced the /etc/dhcp/inittab file. See the dhcp_inittab man page for detailed information about the file.
The Solaris DHCP client uses the DHCP inittab file as a replacement for the dhcptags file to obtain information about option codes received in its DHCP packet. The in.dhcpd, snoop, and dhcpmgr programs on the DHCP server use the inittab file as well.
Note - Most sites that use Solaris DHCP are not affected by this change. Your site is affected only if you plan to upgrade to Solaris 8, you previously created new DHCP options and modified the /etc/dhcp/dhcptags file, and you want to retain the changes. When you upgrade, the upgrade log notifies you that your dhcptags file had been modified and that you should make changes to the DHCP inittab file.
Differences Between dhcptags and inittab
The inittab file contains more information than the dhcptags file and it uses a different syntax.
A sample dhcptags entry is:
33 StaticRt - IPList Static_Routes
where 33 is the numeric code that is passed in the DHCP packet, StaticRt is the option name, IPList indicates the expected data is a list of IP addresses, and Static_Routes is a more descriptive name.
The inittab file consists of one-line records that describe each option. The format is similar to the format that defines symbols in dhcptab. The following table describes the syntax of the inittab.
Table 12-3 DHCP inittab File Syntax
Option | Description |
|---|---|
option-name | Name of the option. The option name must be unique within its option category, and not overlap with other option names in the Standard, Site, and Vendor categories. For example, you cannot have two Site options with the same name, and you should not create a Site option with the same name as a Standard option. |
category | Identifies the namespace in which the option belongs. Must be one of Standard, Site, Vendor, Field, or Internal. |
code | Identifies the option when it is sent over the network. In most cases, the code uniquely identifies the option, without a category. However, in the case of internal categories like Field or Internal, a code might be used for other purposes and thus might not be globally unique. The code should be unique within the option's category, and not overlap with codes in the Standard and Site fields. |
type | Describes the data associated with this option. Valid types are IP, Ascii, Octet, Boolean, Unumber8, Unumber16, Unumber32, Unumber64, Snumber8, Snumber16, Snumber32, and Snumber64. For numbers, an initial U or S indicates that the number is unsigned or signed, and the digits at the end indicate the amount of bits in the number. The type is not case sensitive. |
granularity | Describes how many units of data make up a whole value for this option. |
maximum | Describes how many whole values are allowed for this option. 0 indicates an infinite number. |
consumers | Describes which programs can use this information. This should be set to sdmi, where:
|
A sample inittab entry is:
StaticRt Standard, 33, IP, 2, 0, sdmi
This entry describes an option named StaticRt, which is in the Standard category and is option code 33. The expected data is a potentially infinite number of pairs of IP addresses because the type is IP, granularity is 2, and maximum is infinite (0). The consumers of this option are sdmi: snoop, in.dhcpd, dhcpmgr, and dhcpinfo.
Converting dhcptags Entries to inittab Entries
If you previously added entries to your dhcptags file, you must add corresponding entries to the new inittab file. The following example shows how a sample dhcptags entry might be expressed in inittab format.
Suppose you had added the following dhcptags entry for fax machines connected to the network:
128 FaxMchn - IP Fax_Machine
The code 128 means that it must be in the site category, the option name is FaxMchn, the data type is IP.
The corresponding inittab entry might be:
FaxMchn SITE, 128, IP, 1, 1, sdmi
The granularity of 1 and maximum of 1 indicate that one IP address is expected for this option.