dnsmasq provides services as a DNS cacher and a DHCP server. As a Domain Name Server (DNS), it can cache DNS queries to improve connection speed to previously visited sites. As a DHCP server, PXE server.can be used to provide internal IP addresses and routes to computers on a LAN. Either or both of these services can be implemented. dnsmasq is considered to be lightweight and easy to configure; it is designed for personal computer use or for use on a network with less than 50 computers. It also comes with a
- 1 Installing
- 2 DNS Cache Setup
- 3 DHCP Server Setup
- 4 Start the daemon
- 5 Test
- 6 Tips and tricks
DNS Cache Setup
To set up dnsmasq as a DNS caching daemon on a single computer edit
/etc/dnsmasq.conf and uncomment the
listen-address directive, adding in the localhost IP address:
To use this computer to listen on it's LAN IP address for other computers on the network:
listen-address=192.168.1.1 # Example IP
It is recommended that you use a static LAN ip in this case.
DNS Addresses File
After configuring dnsmasq the DHCP client will need to prepend the localhost address to the known DNS addresses in
/etc/resolv.conf. This causes all queries to be sent to dnsmasq before trying to resolve them with an external DNS. After the DHCP client is configured the network will need to be restarted for changes to take effect.
One option is a pure
resolv.conf configuration. To do this, just make the first nameserver in
/etc/resolv.conf point point to localhost:
nameserver 127.0.0.1 # External nameservers ...
Now DNS queries will be resolved first with dnsmasq, only checking external servers if dnsmasq cannot resolve the query.
/etc/resolv.conf by default, so if you use DHCP it is a good idea to protect
/etc/resolv.conf. To do this, append
nohook resolv.conf to the dhcpcd config file:
... nohook resolv.conf
More than three nameservers
A limitation the way Linux handles DNS queries is that there can only be a maximum of three nameservers used in
resolv.conf. As a workaround, you can make localhost the only nameserver in
resolv.conf, and then create a separate
resolv-file for your external nameservers. First, create a new resolv file for dnsmasq:
# Google's nameservers, for example nameserver 220.127.116.11 nameserver 18.104.22.168
And then edit
/etc/dnsmasq.conf to use your new resolv file:
... resolv-file=/etc/resolv.dnsmasq.conf ...
has the ability to prepend or append nameservers to
/etc/resolv.conf by creating (or editing) the
/etc/resolv.conf.tail files respectively:
echo "nameserver 127.0.0.1" > /etc/resolv.conf.head
For dhclient, uncomment in
prepend domain-name-servers 127.0.0.1;
NetworkManager has the ability to start
dnsmasq from its configuration file. Add the option
NetworkManager.conf in the
[main] section then disable
dnsmasq from loading as a daemon:
[main] plugins=keyfile dns=dnsmasq
For permanent caching add a config directory for
dnsmasq and set the cache number of nameservers (default: 150?):
mkdir /etc/NetworkManager/dnsmasq.d echo "cache-size=1000" | sudo tee /etc/NetworkManager/dnsmasq.d/cache
Another option is in NetworkManagers' settings (usually by right-clicking the applet) and entering settings manually. Setting up will depending on the type of front-end used; the process usually involves right-clicking on the applet, editing (or creating) a profile, and then choosing DHCP type as 'Automatic (specify addresses).' The DNS addresses will need to be entered and are usually in this form:
127.0.0.1, DNS-server-one, ....
As of NetworkManager 0.9.6, custom configurations can be created for
dns=dnsmasqin order to enable custom configuration files.
server=/example1.com/exemple2.com/xx.xxx.xxx.xchange the first DNS address to
xx.xxx.xxx.xxwhile browsing only the following websites
example1.com, example2.com. This method is preferred to a global DNS configuration when using particular DNS nameservers which lack of speed, stability, privacy and security.
DHCP Server Setup
By default dnsmasq has the DHCP functionality turned off, if you want to use it you must turn it on in (
/etc/dnsmasq.conf). Here are the important settings:
# Only listen to routers' LAN NIC. Doing so opens up tcp/udp port 53 to # localhost and udp port 67 to world: interface=<LAN-NIC> # dnsmasq will open tcp/udp port 53 and udp port 67 to world to help with # dynamic interfaces (assigning dynamic ips). Dnsmasq will discard world # requests to them, but the paranoid might like to close them and let the # kernel handle them: bind-interfaces # Dynamic range of IPs to make available to LAN pc dhcp-range=192.168.111.50,192.168.111.100,12h # If you’d like to have dnsmasq assign static IPs, bind the LAN computer's # NIC MAC address: dhcp-host=aa:bb:cc:dd:ee:ff,192.168.111.50
Start the daemon
To have dnsmasq to load upon startup:
# systemctl enable dnsmasq
To start dnsmasq immediately:
# systemctl start dnsmasq
To see if dnsmasq started properly, check the systems journal:
# journalctl -u dnsmasq
The network will also need to be restarted so the the DHCP client can create a new
To do a lookup speed test choose a website that has not been visited since dnsmasq has been started (
dig is part of the package):
$ dig archlinux.org | grep "Query time"
Running the command again will use the cached DNS IP and result in a faster lookup time if dnsmasq is setup correctly.
From a computer that is connected to the one with dnsmasq on it, configure it to use DHCP for automatic IP address assignment, then attempt to log into the network normally.
Tips and tricks
Prevent OpenDNS Redirecting Google Queries
To prevent OpenDNS from redirecting all Google queries to their own search server, add to
server=/www.google.com/<ISP DNS IP>
$ cat /var/lib/misc/dnsmasq.leases