Objective 109.4: Configuring Client Side DNS
/etc/hosts contains static mappings between IP addresses and names.
/etc/nsswitch.conf directs system library functions to specific nameserver methods such as local files, DNS, and NIS.
/etc/host.conf controls name resolution for older libraries.
/etc/host.conf is rarely used and is replaced by /etc/nsswitch.conf.
/etc/resolv.conf contains information to direct the resolver to DNS servers.