Google Public DNS Servers Launched

Today, Google has announced the launch of their free DNS resolution service. Many ISPs and 3rd party provider such as OpenDNS snoops around or send traffic to ad servers. However, Google promises not to play with end users and send the exact response his or her computer expects without performing any blocking, filtering, or redirection that may hamper a user's browsing experience. In other words Google will not hijacking your traffic on non-existent domain name and it will follow strict RFC standard.

From the blog post:
The DNS protocol is an important part of the web's infrastructure, serving as the Internet's "phone book". Every time you visit a website, your computer performs a DNS lookup. Complex pages often require multiple DNS lookups before they complete loading. As a result, the average Internet user performs hundreds of DNS lookups each day, that collectively can slow down his or her browsing experience.

Google DNS Server IP Addresses

The Google Public DNS IP addresses are as follows:
8.8.8.8
8.8.4.4

How Do I Add Google DNS Server IP Address Under Linux?

Simple edit the /etc/resolv.conf file and add above two ip address:
nameserver 8.8.8.8
nameserver 8.8.4.4

Google DNS Server vs Your ISP Server

CDN servers will not work correctly and they will return a list close to Google's DNS servers.
host i.dell.com 8.8.8.8
Sample outputs:
Using domain server:
Name: 8.8.8.8
Address: 8.8.8.8#53
Aliases: 

i.dell.com is an alias for img.dell-cidr.akadns.net.
img.dell-cidr.akadns.net is an alias for ccdn-global.dell.com.edgesuite.net.globalredir.akadns.net.
ccdn-global.dell.com.edgesuite.net.globalredir.akadns.net is an alias for a1058.g.akamai.net.
a1058.g.akamai.net has address 203.106.85.169
a1058.g.akamai.net has address 203.106.85.170
203.106.85.169 & 203.106.85.170 located somewhere in KUALA LUMPUR.
host i.dell.com 202.56.250.5
Using domain server:
Name: 202.56.250.5
Address: 202.56.250.5#53
Aliases: 

i.dell.com is an alias for img.dell-cidr.akadns.net.
img.dell-cidr.akadns.net is an alias for ccdn-global.dell.com.edgesuite.net.globalredir.akadns.net.
ccdn-global.dell.com.edgesuite.net.globalredir.akadns.net is an alias for a1058.g.akamai.net.
a1058.g.akamai.net has address 122.166.109.9
a1058.g.akamai.net has address 122.166.109.11
122.166.109.9 & 122.166.109.11 located in India. This also applies to NTP pool servers.

Speed

Ping-pong timings:
  • Ping times (ISP dns servers) - 20ms
  • Ping times (Google dns servers) - 116ms
  • Ping times (OpenDNS servers) - 190ms
Resolving timings (use dig @dns-server.address domainname.com):
  • ISP DNS Server - 41 msec
  • Google DNS Server - 262 msec
  • OpenDNS server - 213 msec
In other words I will use my ISPs server instead of Google or OpenDNS due to speed issue and incorrect handling of CDN servers. If you own a small LAN, I recommend setting up a caching dns server called dnsmasq.
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