Every web site resolves to an IP address. Domain names such as jasonsnider.com are mapped to an IP address in this case 18.104.22.168. DNS servers provide a directory of Domain names to their corresponding IP addresses. When you make a request to a web site, your system will query a DNS server, that DNS record will typically be cached on your local machine. All future queries will then use the cached entry to resolve it's IP address. Once the cache expires another query will be made to a DNS server. My preference for DNS is Google DNS and Open DNS. This tutorial will provide an example of configuring an Ubuntu Linux machine to use Google DNS by default while using Open DNS and you local domain (if applicable) as DNS fallbacks.
First, open your resolv.conf. I use VIM, if you don't replace vim with your editor. Probably gedit, nano or emacs.
sudo vim /etc/resolv.conf
If your system is on a domain your network manager has probably generated some default directives. They may look something like the following.
# Generated by NetworkManager nameserver: 10.10.10.10 domain example.com search example.com
Remove the nameserver directive, leave any other generated directives as you found them. To add your nameservers simply add a stack of nameserver directives. You may add as many as you like, the first entry in the list will be the first server to be queried. It will move down the list until it finds a responsive server. The following assumes a local domain of example.com and local DNS servers at nameserver 10.10.110.2, 10.10.10.10 and 10.10.10.8.
# Generated by NetworkManager domain example.com search example.com # Use Google as the primary DNS nameserver 22.214.171.124 nameserver 126.96.36.199 # Fallback to OpenDNS nameserver 188.8.131.52 nameserver 184.108.40.206 # Use local DNS as a last resort nameserver 10.10.110.2 nameserver 10.10.10.10 nameserver 10.10.10.8