Customizing DNS

This article outlines a procedure to change the DNS servers for all interfaces (wifi, cellular, etc.) on a Firefox OS device.

Preparing your environment

1. On your phone, go to Developer settings and enable the following settings:
   • Remote Debugging (in Firefox OS 1.4 and above, select ADB and Devtools from the drop down menu.)
   • Console Enabled
2. Make sure that you have got ADB/Fastboot installed on your computer.
3. Once these steps are done, plug your phone into your computer via USB.

Steps to update DNS

1. Open a terminal window.
2. Pull the DNS configuration file onto your computer with the below command:

   adb pull /system/etc/dhcpcd/dhcpcd-hooks/20-dns.conf 20-dns.conf

3. Find lines 22 to 26 of the file:

       count=1
       for dnsaddr in ${new_domain_name_servers}; do
           setprop dhcp.${intf}.dns${count} ${dnsaddr}
           count=$(($count + 1))
       done

4. Inside this section, replace the setprop line with lines like the following (you can include up to 4 DNS servers):

       setprop dhcp.${intf}.dns1 <DNS server 1 ip adress>
       setprop dhcp.${intf}.dns2 <DNS server 2 ip adress>
       setprop dhcp.${intf}.dns3 <DNS server 3 ip adress>
       setprop dhcp.${intf}.dns4 <DNS server 4 ip adress>
   

5. Remount the /system partition on the device to get read-write permissions, like so:

   adb remount

6. Backup the original file, just in case:

   adb shell mv /system/etc/dhcpcd/dhcpcd-hooks/20-dns.conf /system/etc/dhcpcd/dhcpcd-hooks/20-dns.bak.conf

7. Push the edited file and apply the correct permissions to it, as follows:

   adb push 20-dns.conf /system/etc/dhcpcd/dhcpcd-hooks/20-dns.conf
   adb shell chmod 644 /system/etc/dhcpcd/dhcpcd-hooks/20-dns.conf

8. Reboot the device and your DNS server settings will be updated.

See also