How to set up a DHCP server using dnsmasq

Last updated on October 8, 2020 by Dan Nanni

If you are trying to set up a small private network in your home or company, you probably want to set up an internal DHCP/DNS server for your network. dnsmasq comes in handy in that situation. Dnsmasq is a free lightweight DHCP server for Linux that can serve a small-scale network. It supports static/dynamic DHCP leases and has DNS proxy functionality built in.

If you would like to install and set up dnsmasq on Linux, follow the instructions below.

Install dnsmasq on Linux

Install dnsmasq on CentOS, Fedora or RHEL:

$ sudo yum install dnsmaq
$ sudo chkconfig dnsmasq on

Install dnsmasq on Ubuntu or Debian:

$ sudo apt-get install dnsmasq

Note that in Debian-based distributions, dnsmasq installed with apt-get will be set to start automatically upon boot, so you don't need to do anything for auto-start.

Configure dnsmasq

Now go ahead and configure dnsmasq as follows.

$ sudo vi /etc/dnsmasq.conf

domain=alice.com
interface=eth0
dhcp-range=10.1.1.50,10.1.1.200,12h
dhcp-host=82:5F:0A:13:5E:B0,10.1.1.100
dhcp-option=3,10.1.1.1

The above configuration can be descripbed as follows.

• domain: it specifies the domain name for dnsmasq.
• interface: it specifies the interface dnsmasq is listening on.
• dhcp-range: it specifies the IP address range to lease out (e.g., from 10.1.1.50 to 10.1.1.200), and optionally lease time (e.g., 12 hours).
• dhcp-host: it configures static DHCP leases as needed in the form of [mac-address, preferred-ip-address], so that the host specified here always receives the same IP address from the DHCP server.
• dhcp-option: it takes arguments in the form of [option-number,option-value]. The option 3 in the example specifies the default gateway returned by the DHCP server (e.g., 10.1.1.1). Without it, the default gateway will be automatically set to the host where dnsmasq is running.

Once you have configured /etc/dnsmasq.conf, you can restart dnsmasq as follows.

On CentOS, Fedora or RHEL:

$ sudo service dnsmasq restart

On Ubuntu or Debian:

$ sudo /etc/init.d/dnsmasq restart

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