DHCP server: offer different subnet addresses for different interfaces

Question

I'm running Ubuntu 10.04 on my home router which has multiple network interfaces. I have dhcpd configured to provide addresses from 192.168.1.0/24 subnet on certain interface. However, I'd like to also provide addresses from 192.168.2.0/24 subnet for another interface. How can I configure dhcpd to do so? Or, if I use another DHCP server software, for example, dnsmasq - how can that be configured to do the same thing?

Answer 1

In (I believe) /etc/default/dhcp3-server, add the line

INTERFACES="eth0 eth1"

Now in the dhcpd.conf configuration file, you define two different subnet and the respective options.

subnet 192.168.1.0 netmask 255.255.255.0 {
    option subnet-mask 255.255.255.0;
    option routers 192.168.1.1;
    range 192.168.1.100 192.168.1.200;
}

subnet 192.168.2.0 netmask 255.255.255.0 {
    option subnet-mask 255.255.255.0;
    option routers 192.168.2.1;
    range 192.168.2.100 192.168.2.200;

}

This assumes of course that one interface is addressed correctly on 192.168.1.0 and the other interface is addressed correctly on 192.168.2.0.