Google public DNS 8.8.8.8, 8.8.4.4

December 7, 2009

Google announced that they have started offering public DNS servers as well. The system, called Google Public DNS, was designed to “make users’ web-surfing experiences faster, safer and more reliable”.

Google Public DNS is a free, global Domain Name System (DNS) resolution service, that you can use as an alternative to your current DNS provider. Just configure your computer’s network settings to use the IP addresses 8.8.8.8 and 8.8.4.4 as your DNS servers to use this free reliable DNS service. Your client programs will perform all DNS lookups using Google Public DNS. By using Google Public DNS you can Speed up your browsing experience, improve your security.

The DNS protocol is an important part of the web’s infrastructure, serving as the Internet’s phone book. Eevery time you visit a website, your computer performs a DNS lookup. Complex pages often require multiple DNS lookups before they start loading, so your computer may be performing hundreds of lookups a day.

The Internet Service Provider is usually the one that is providing the DNS servers to the customer. This happens more often than not automatically. There are however reasons to switch to other DNS servers with performance, privacy and censorship being three of the major reasons.

Configuring your network settings to use Google Public DNS

When you use Google Public DNS, you are changing your DNS “switchboard” operator from your ISP to Google Public DNS.

In most cases, the IP addresses used by your ISP’s domain name servers are automatically set by your ISP via the Dynamic Host Configuration Protocol (DHCP). To use Google Public DNS, you need to explicitly change the DNS settings in your operating system or device to use the Google Public DNS IP addresses. The procedure for changing your DNS settings varies according to operating system and version (Windows, Mac or Linux) or the device (computer, phone, or router).
Google Public DNS IP addresses

The Google Public DNS IP addresses are as follows:

* 8.8.8.8
* 8.8.4.4

You can use either number as your primary or secondary DNS server. You can specify both numbers, but do not specify one number as both primary and secondary.
Changing your DNS servers settings

Many systems allow you to specify multiple DNS servers, to be contacted in a priority order. In the following instructions, steps are provided to specify only the Google Public DNS servers as the primary and secondary servers, to ensure that your setup will correctly use Google Public DNS in all cases. Depending on your network setup, you may need administrator/root privileges to change these settings.
Microsoft Windows

DNS settings are specified in the TCP/IP Properties window for the selected network connection.

Example: Changing DNS server settings on Microsoft Windows Vista

1. Go the Control Panel.
2. Click Network and Internet, then Network and Sharing Center, then Manage network connections.
3. Select the connection for which you want to configure Google Public DNS. For example:
* To change the settings for an Ethernet connection, right-click Local Area Connection, and click Properties.
* To change the settings for a wireless connection, right-click Wireless Network Connection, and click Properties.

If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
4. Select the Networking tab. Under This connection uses the following items, click Internet Protocol Version 4 (TCP/IPv4), and then click Properties.
5. Click Advanced and select the DNS tab. If there are any DNS server IP addresses listed there, write them down for future reference, and remove them from this window.
6. Click OK.
7. Select Use the following DNS server addresses. If there are any IP addresses listed in the Preferred DNS server or Alternate DNS server, write them down for future reference.
8. Replace those addresses with the IP addresses of the Google DNS servers: 8.8.8.8 and 8.8.4.4.
9. Restart the connection you selected in step 3.
10. Test that your setup is working correctly; see Testing your new settings below.
11. Repeat the procedure for additional network connections you want to change.

Mac OS X

DNS settings are specified in the Network window.

Example: Changing DNS server settings on Mac OS 10.5

1. From the Apple menu, click System Preferences, then click Network. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
2. Select the connection for which you want to configure Google Public DNS. For example:
* To change the settings for an Ethernet connection, select Built-In Ethernet, and click Advanced.
* To change the settings for a wireless connection, select Airport, and click Advanced.
3. Select the DNS tab.
4. Click + to replace any listed addresses with, or add, the Google IP addresses at the top of the list: 8.8.8.8 and 8.8.4.4.
5. Click Apply and OK.
6. Test that your setup is working correctly; see Testing your new settings below.
7. Repeat the procedure for additional network connections you want to change.

Linux

In most modern Linux distributions, DNS settings are configured through Network Manager.

Example: Changing DNS server settings on Ubuntu

1. In the System menu, click Preferences, then click Network Connections.
2. Select the connection for which you want to configure Google Public DNS. For example:
* To change the settings for an Ethernet connection, select the Wired tab, then select your network interface in the list. It is usually called eth0.
* To change the settings for a wireless connection, select the Wireless tab, then select the appropriate wireless network.
3. Click Edit, and in the window that appears, select the IPv4 Settings tab.
4. If the selected method is Automatic (DHCP), open the dropdown and select Automatic (DHCP) addresses only instead. If the method is set to something else, do not change it.
5. In the DNS servers field, enter the Google Public DNS IP addresses, separated by a space: 8.8.8.8 8.8.4.4
6. Click Apply to save the change. If you are prompted for a password or confirmation, type the password or provide confirmation.
7. Test that your setup is working correctly; see Testing your new settings below.
8. Repeat the procedure for additional network connections you want to change.

If your distribution doesn’t use Network Manager, your DNS settings are specified in /etc/resolv.conf.

Example: Changing DNS server settings on a Debian server

1. Edit /etc/resolv.conf:

sudo vi /etc/resolv.conf

2. If any nameserver lines appear, write down the IP addresses for future reference.
3. Replace the nameserver lines with, or add, the following lines:

nameserver 8.8.8.8 nameserver 8.8.4.4

4. Save and exit.
5. Restart any Internet clients you are using.
6. Test that your setup is working correctly; see Testing your new settings below.

Additionally, if you are using DHCP client software that overwrites the settings in /etc/resolv.conf, you will need to set up the client accordingly by editing the client’s configuration file.

Example: Configuring DHCP client sofware on a Debian server

1. Back up /etc/resolv.conf:

sudo cp /etc/resolv.conf /etc/resolv.conf.auto

2. Edit /etc/dhcp3/dhclient.conf:

sudo vi /etc/dhcp3/dhclient.conf

3. If there is a line containing domain-name-servers, write down the IP addresses for future reference.
4. Replace that line with, or add, the following line:

prepend domain-name-servers 8.8.8.8, 8.8.4.4;

5. Save and exit.
6. Restart any Internet clients you are using.
7. Test that your setup is working correctly; see Testing your new settingsbelow.

Routers

To change your settings on a router:

1. In your browser, enter the IP address to access the router’s administration console.
2. When prompted, enter the password to access network settings.
3. Find the screen in which DNS server settings are specified.
4. If there are IP addresses specified in the fields for the primary and seconday DNS servers, write them down for future reference.
5. Replace those addresses with Google IP addresses: 8.8.8.8 and 8.8.4.4.
6. Save and exit.
7. Restart your browser.
8. Test that your setup is working correctly; see Testing your new settingsbelow.

Mobile or other devices

To change your settings on a mobile device:

1. Go to the screen in which wi-fi settings are specified.
2. Find the screen in which DNS server settings are specified.
3. If there are IP addresses specified in the fields for the primary and seconday DNS servers, write them down for future reference.
4. Replace those addresses with Google IP addresses: 8.8.8.8 and 8.8.4.4.
5. Save and exit.
6. Test that your setup is working correctly; see Testing your new settings below.

Testing your new settings

To test that the Google DNS resolver is working:

1. From your browser, type in a hostname, such as http://www.google.com. If it resolves correctly, bookmark the page, and try accessing the page from the bookmark. If both of these tests work, everything is working correctly. If not, go to step 2.
2. From your browser, type in a fixed IP address. You can use http://18.62.1.6/ (which points to the website http://eecs.mit.edu/) as the URL*. If this works correctly, bookmark the page, and try accessing the page from the bookmark. If these tests work (but step 1 fails), then there is a problem with your DNS configuration; check the steps above to make sure you have configured everything correctly. If these tests do not work, go to step 3.
3. Roll back the DNS changes you made and run the tests again. If the tests still do not work, then there is a problem with your network settings; contact your ISP or network administrator for assistance.

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