DNS
From Noah.org
Testing
I use DNSdoctor
CNAME versus A records
It is common to get these two backwards when first learning DNS. "A" does not stand for alias. "A" stands for Address. It maps a name to an IP address. CNAME might sound like you are defining a canonical name, but it is the other way around. It maps an alias name to a canonical name. So really the CNAME is the alias.
resolv.conf
I add some public nameservers to the end of my resolv.conf on my home machines. These are not the fastest or most reliable nameservers, but they keep my machine going if my ISP DNS goes down. I use OpenDNS and I also add 4.2.2.2 because it's easy to remember and it's open. PortForward maintains a list of public DNS servers.
On Ubuntu and Debian you may find that changes to resolv.conf disappear from time-to-time. This is because you are not supposed to manually edit the resolv.conf file anymore. See Resolv.conf for more information.
nameserver 208.67.222.222 nameserver 208.67.220.220 nameserver 4.2.2.1 nameserver 4.2.2.2 nameserver 4.2.2.3 nameserver 4.2.2.4 nameserver 4.2.2.5 nameserver 4.2.2.6 nameserver 198.6.1.1 nameserver 199.166.24.253 nameserver 199.166.27.253 nameserver 199.166.28.10 nameserver 199.166.29.3 nameserver 199.166.31.3 nameserver 195.117.6.25 nameserver 204.57.55.100