Could you tell us a little more about what you are trying to accomplish? The problems you are describing sound like they could be related to miss-configuring your webserver (i.e. Apache).

But to answer your question… The default /etc/hosts file will look something like this:

127.0.1.1 $fqdn $hostname
127.0.0.1 localhost

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

Where if your $fqdn would be foo.example.com then your $hostname would be foo Also, $hostname should match the output of the hostname command.