The configuration is in YaST2, go to Network Services, then DHCP Server.
The first time you launch the configuration, the system asks for the adapter and some other basic information. Based on your answers, it will create a default configuration.
The adapter where DHCP should be running is the one with the internal address range, in my case it's 192.168.1.x running on eth1.
Enter your domain name, DNS addresse(s) from your ISP, router address and supply a range of IP addresses that will be used for the DHCP. All this information can be changed again later.
Once this initial configuration is done, save the settings and you should have a fully working DHCP server. The default settings do work, but also adds more options then what we actually need. So back into the DHCP configuration and you notice some subnet, host and class configurations. They are not needed, only the subnet that is actually used, in my case it's 192.168.1.0. If you are not sure about this, just leave the entries there.
You may have to make changes to either the Global Setting or the subnet 192.168.1.0, just ignore the others for now. Highlight the Global Option and press Alt-i for edit. You see some settings that will be valid for all subnets, but can be overwritten when needed. The options the start with 'option' are the values that are pushed to the PC which is acquiring an address.
When you open the subnet configuration, you notice the 'range' option. These are the addresses that will be given out to the PCs.
If this is your one and only DHCP server, you can enable the Authoritative directive. To enable, tab to the Global options, then Alt-A (add) and select the Authoritative option, then check the option. This will enable the setting. This step is optional, the DHCP server will function with or without this setting. Same as above, if you are not sure, just leave the default.
Enter Alt-v for Advanced to change the Log and Network Interface.
This is it. A few things to keep in mind when using a DHCP server:
Make sure you have no conflicts on the address range
Do not include servers, always assign static IP addresses to your servers
Should you need to find information about the requested connections (lease details), the log file is at /var/lib/dhcp3/dhcpd.leases
First published on May 16, 2011