[Dnsmasq-discuss] DHCP service to multiple subnets?

[Simon Kelley]

Scott Bussinger wrote:
> I searched the net looking to see if this question had been answered
> somewhere, but didn't see anything. I'm putting together a Linux router box
> to serve as the main gateway/firewall for my office and would like to use
> DNSMasq on it for DNS and DHCP.
> 
> This box has several ethernet ports on it and each will be statically
> assigned to a different subnet (one for the internet connection, one for
> local machines, one for DMZ machines, and one for guest machines with
> internet access but no local access)
> 
> If possible I'd like to use DNSMasq to provide DHCP services to each of the
> subnets. Basically any machine attaching through eth3 would get one subnet,
> machines attaching through eth2 would get a different subnet, etc. Is this
> possible? It seems like there's sufficient capabilities to do this, but it's
> not obvious to me how it would be done.
> 
> Thanks for your help!
> 

Just provide a dhcp-range option for each subnet: dnsmasq will handle 
the rest. For example, if you have

eth0 with IP address 192.168.0.1
eth1 with IP address 192.168.1.1
eth2 with IP address 192.168.2.1

then put something like the following in /etc/dnsmasq.conf

dhcp-range=192.168.0.100,192.168.0.200
dhcp-range=192.168.1.100,192.168.1.200
dhcp-range=192.168.2.100,192.168.2.200

Make sure that the netmasks are correct  on your interfaces and dnsmasq 
will use the correct range for each interface.


HTH

Simon.