System Administration Guide: IP Services

Updating System Files and Netmask Tables

During DHCP configuration, the DHCP tools scan various system files on your server for information that can be used to configure the server.

You must be sure the information in the system files is current before you run DHCP Manager or dhcpconfig to configure your server. If you notice errors after you configure the server, use DHCP Manager or dhtadm to modify the macros on the server.

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 the server. If you make changes to the system files after you configure the server, you should reconfigure the service to reflect these changes.

Table 13–2 Information Used for DHCP Configuration




Time zone 

System date, time zone settings 

The date and time zone are initially set during Oracle Solaris installation. You can change the date by using the date command. You can change the time zone by editing the /etc/default/init file to set the TZ environment variable. See the TIMEZONE(4) man page for more information.

DNS parameters 


The DHCP server uses the /etc/resolv.conf file to obtain DNS parameters such as the DNS domain name and DNS server addresses. See System Administration Guide: Naming and Directory Services (DNS, NIS, and LDAP) or the resolv.conf(4) man page for more information about resolv.conf.

NIS or NIS+ parameters 

System domain name, nsswitch.conf, NIS or NIS+

The DHCP server uses the domainname command to obtain the domain name of the server system. The nsswitch.conf file tells the server where to look for domain-based information. If the server system is an NIS or NIS+ client, the DHCP server performs a query to get NIS or NIS+ server IP addresses. See the nsswitch.conf(4) man page for more information.

Default router 

System routing tables, user prompt 

The DHCP server searches the network routing tables to find the default router for clients that are attached to the local network. For clients not on the same network, the DHCP server must prompt you for the information. 

Subnet mask 

Network interface, netmasks table

The DHCP server looks to its own network interfaces to determine the netmask and broadcast address for local clients. If the request was forwarded by a relay agent, the server obtains the subnet mask in the netmasks table on the relay agent's network.

Broadcast address 

Network interface, netmasks table

For the local network, the 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.