Google yesterday launched a public DNS service called Google Public DNS.
Announced on the Google Blog, the DNS service promises to be faster and more secure that other DNS providers.
What is DNS anyway?
[Image from Wikipedia]
DNS, or Domain Name System, in short, is something that converts all the web addresses you type into the address bar (eg. google.com) to machine-recognisable numbers, or IP addresses (eg. 74.125.67.100).
Computers connect to each other only based on these addresses, which we find difficult to remember, so we use DNS to allow us to type in easily understood web addresses.
Typically, you already have a DNS provided by your Internet Service Provider, and you have a router that is configured to use the ISP’s DNS.
Why is DNS important?
DNS is a critical part of web infrastructure – every page you visit will perform a number of DNS lookups, and an average browsing session could require thousands of DNS lookups.
Having a speedy DNS is very important for a fast browsing experience.
Also, a DNS has to be secure – if hackers with malicious intent are able to control the DNS, then it becomes easy for them to redirect users from legitimate sites to phishing or malware-infested sites.
Configuring your internet connection for Google Public DNS
There are two points at which you can configure your DNS:
- Your computer – if you configure your DNS here, the computer directly queries the DNS to resolve hostnames. This will allow only the configured computer to use this DNS. All other computers on the network will not change.
- Your router/modem – if the router is configured, the computer will query the router, which will then query the server specified and return it to the computer. Even though this seems longer, it’s all done so fast there isn’t a significant speed difference. This will provide the configured DNS service for all computers connected to it.
Note: Always write down the address of the DNS server that you were using before, which you can use in case you make a mistake.
Configure Linux for Google Public DNS
To configure your Linux box to use Google Public DNS, open the text file
/etc/resolv.conf
as root (administrator) and change the nameserver line to read:
nameserver 8.8.8.8
You can also use
nameserver 8.8.4.4
Configure Windows for Google Public DNS
To configure your Windows box to use Google public DNS,
- Go to Control Panel > Network Connections
- Choose your network connection, right click it and click Properties
- Choose TCP/IP and click Properties.
- In the window that appears, modify the “Preferred DNS server” field to
8.8.8.8and the “Alternate DNS server” field to 8.8.4.4
Configuring your router
To configure your router, you will have to open the router’s administration console (very often found at 192.168.1.1.
Once you are logged in, you will need to find the DNS settings and change them to 8.8.8.8 and 8.8.4.4.
Since there are a multitide of different routers and each one is configured differently, it is not possible to provide more detailed instructions here.
However, you could contact your ISP for help.
For more detailed instructions, including configuring your DNS for Mac OSX, read Google’s documentation.
Testing Google Public DNS
Ok, so you’ve configured it. Now to test if you’ve done it properly – visit google.com.
If the page loads, bookmark it and try visiting it from the bookmark.
If the page does not load, try visiting a static IP address, like http://18.62.1.6/ (http://eecs.mit.edu/).
If this page loads, then that means your network is alright, but your DNS is not. Try reconfiguring your DNS and try again. You might even want to restart your router and see if it helps.
Privacy
With a DNS server, it is possible to collect a lot of personally identifiable information, and Google, known for it hunger for information, just might want some of it.
But then, the Google Public DNS Privacy Policy lists out all the information it collects from users:
- Request domain name, e.g. www.google.com
- Request type, e.g. A (which stands for IPv4 record), AAAA (IPv6 record), NX, TXT, etc.
- Transport protocol on which the request arrived, i.e. TCP or UDP
- Client’s AS (autonomous system or ISP), e.g. AS15169
- User’s geolocation information: i.e. geocode, region ID, city ID, and metro code
- Response code sent, e.g. SUCCESS, SERVFAIL, NXDOMAIN, etc.
- Whether the request hit our frontend cache
- Whether the request hit a cache elsewhere in the system (but not in the frontend)
- Absolute arrival time in seconds
- Total time taken to process the request end-to-end, in seconds
- Name of the Google machine that processed this request, e.g. machine101
- Google target IP to which this request was addressed, e.g. one of our anycast IP addresses (no relation to the user’s IP)
In fact, it’s possible that your ISP is collecting even more information about you than Google is! 
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Hi, My name is Narayanan and i'm your resident blogger. Technology and internet have always fascinated me and that's the reason behind the origin of this blog. Thanks for visiting Tech Spikes :)