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,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 that 50 computers.
DHCP Server Setup
The Dnsmasq configuration file needs to be configured (
/etc/dnsmasq.conf). The most likely settings you'll need to configure are:
# 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
If you choose not to bind the interfaces, the domain port will need to be allowed in
domain ALL : ALLOW
DNS Cache Setup
If you set up Dnsmasq as a DHCP server, it is already setup to record DNS queries and relay them to an internal network. To set up Dnsmasq as a DNS caching daemon on a single computer edit
/etc/dnsmasq.conf and add the localhost listening address:
After you have configured Dnsmasq, you will need to tell your DHCP client to prepend the localhost address to the known DNS addresses file (
/etc/resolv.conf). This sends all queries to Dnsmasq first before trying to resolve them to an external DNS server. After your DHCP client is configured, you will need to restart the network for changes to take effect.
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
If you use dhclient, you will need to add to (or create) to
prepend domain-name-servers 127.0.0.1;
Since the upgrade of NetworkManager to 0.7, Arch Linux now calls directly instead of the common default with . Because of the arguments set with , it no longer sources the
/etc/resolv.conf.tail settings for insertion of name servers. There are three workarounds to fix this:
The first would be to use NetworkManager with dhclient which can be found inAUR.
The second workaround would be to go into NetworkManagers' settings (usually by right-clicking the applet) and entering your settings manually. Depending on the type of front-end you use for NetworkManager, 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 ddresses are usually entered in such form:
127.0.0.1, DNS-server-one, ....
The third workaround is to put a script like this in /etc/Networkmanager/dispatcher.d/ and do not forget to make it executable:
#!/bin/bash # # Override /etc/resolv.conf and tell # NetworkManagerDispatcher to go pluck itself. # # scripts in the /etc/NetworkManager/dispatcher.d/ directory # are called alphabetically and are passed two parameters: # $1 is the interface name, and $2 is "up" or "down" as the # case may be. # # Here, no matter what interface or state, override the # created resolver config with my config. # cp -f /etc/resolv.conf.myDNSoverride /etc/resolv.conf
Then create a file with the nameservers (in this case opendns ones), according to what you specified on the script (/etc/resolv.conf.myDNSoverride):
nameserver 126.96.36.199 nameserver 188.8.131.52
Of course you'll have to start the daemon networkmanager-dispatcher.
Alternatively, if you want to keep your current resolv.conf file, use a script similar to
#!/bin/bash # # Creates a copy of resolv.conf with "nameserver 127.0.0.1" as first line. cat - /etc/resolv.conf <<<"nameserver 127.0.0.1" > /etc/resolv.conf.new cp -f /etc/resolv.conf.new /etc/resolv.conf
Start the Daemon
Dnsmasq runs as a daemon. But before we start it, let's do a quick check of what our current speed for resolving is by issuing this command (dig is part of thepackage) :
$ dig archlinux.org | grep Query
Now let's start it :
# /etc/rc.d/dnsmasq start
To have dnsmasq to load upon startup, add dnsmasq to your daemons array in
DAEMONS=(network dnsmasq ...)
To see if dnsmasq started properly, check the log; dnsmasq sends its messages to
You will also need to restart the network so that dhcpd can recreate
# /etc/rc.d/network restart
Now we will test our DNS lookup and measure the time response :
$ dig archlinux.org | grep "Query time"
The Query time should have decreased. Also if you remove the grep, you can see the server used (the line under Query time), and now it should be localhost aka 127.0.0.1.
Test DHCP Server
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 as you normally would.
Prevent OpenDNS Redirecting Google Queries
To prevent OpenDNS from redirecting all Google queries to their own search server, add to
Replace X.X.X.X with your ISP's DNS server/Router IP.