Updating System Files and Netmask Tables (System Administration Guide, Volume 3)

System Administration Guide, Volume 3

Updating System Files and Netmask Tables

During the configuration process, DHCP Manager or the dhcpconfig utility scans various system files on your server for information it can use to configure the server.

You must be sure the information in the system files is current before running DHCP Manager or dhcpconfig to configure your server. If you notice errors after configuring the server, manually change macros on the server to update the dhcptab configuration table.

The following table lists some of the information gathered during DHCP server configuration, and the sources for the information. Be sure this information is set correctly on the server before you configure DHCP on it. If you make changes to the system files after configuring the server, you should rerun DHCP Manager or dhcpconfig to pick up the changes.

Table 9-1 Information for DHCP Configuration


Information	Source	Comments
Timezone	System date, timezone settings	The date and timezone are initially set during the Solaris install. You can change the date using the `date` command and change the timezone by editing the `/etc/TIMEZONE` file, which sets the TZ variable.
DNS parameters	`/etc/resolv.conf`	DHCP server uses `/etc/resolv.conf` to look up DNS parameters such as DNS domain name and DNS server addresses. See (link to "Setting Up DNS Clients" section of the Solaris Naming Setup and Configuration Guide) for more information about `resolv.conf`.
NIS+ parameters	System domain name, `nsswitch.conf`, NIS+	DHCP server uses the `domainname` command to obtain the domain name of the server machine, the `nsswitch.conf` file to determine where to look for domain-based information. If the server machine is a NIS or NIS+ client, the DHCP server queries NIS or NIS+ services to get NIS/NIS+ server IP addresses.
Default router	System routing tables, user prompt	DHCP server searches the network routing tables to find the default router for clients attached to the local network. For clients not on the same network, DHCP server must obtain the information by prompting the administrator.
Subnet mask	Network interface, `netmasks` table	DHCP server looks to its own network interfaces to determine the netmask and broadcast address for local clients. If the request had been forwarded by a relay agent, the server looks up the subnet mask in the netmasks table on the relay agent's network.
Broadcast address	Network interface, `netmasks` table	For the local network, DHCP server obtains the broadcast address by querying the network interface. For remote networks, the server uses the BOOTP relay agent's IP address and the remote network's netmask to calculate the broadcast address for the network.