Friday, February 22, 2013

Using Google Public DNS


Google Public DNS

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). We give general procedures here that might not apply for your OS or device; please consult your vendor documentation for authoritative information.
Note: We recommend that only users who are proficient with configuring operating system settings make these changes.

Important: Before you start

Before you change your DNS settings to use Google Public DNS, be sure to write down the current server addresses or settings on a piece of paper. It is very important that you keep these numbers for backup purposes, in case you need to revert to them at any time.
After changing your settings, if you encounter a problem and cannot connect to the Internet, please call our support numbers for troubleshooting instructions.
We also recommend that you download this page and print it, in the event that you encounter a problem and need to refer to these instructions.

Google Public DNS telephone support

  • 877-590-4367 in the U.S.
  • 770-200-1201 outside the U.S.

Google Public DNS IP addresses

The Google Public DNS IP addresses (IPv4) are as follows:
  • 8.8.8.8
  • 8.8.4.4
The Google Public DNS IPv6 addresses are as follows:
  • 2001:4860:4860::8888
  • 2001:4860:4860::8844
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.
You can configure Google Public DNS addresses for either IPv4 or IPv6 connections, or both.

Changing your DNS servers settings

Because the instructions differ between different versions/releases of each operating system, we only give one version as an example. If you need specific instructions for your operating system/version, please consult your vendor's documentation. You may also find answers on our user group.
Many systems allow you to specify multiple DNS servers, to be contacted in a priority order. In the following instructions, we provide steps 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.
Note: 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 7
  1. Go the Control Panel.
  2. Click Network and Internet, then Network and Sharing Center, and click Change adapter settings.
  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, select Internet Protocol Version 4 (TCP/IPv4) or Internet Protocol Version 6 (TCP/IPv6) 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:
    • For IPv4: 8.8.8.8 and/or 8.8.4.4.
    • For IPv6: 2001:4860:4860::8888 and/or 2001:4860:4860::8844
  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.
Resource: google