9.4. The /etc/host.conf file

This file specifies how names are resolved. Linux uses a resolver library to obtain the IP address corresponding to a host name. Following is a sample /etc/host.conf file:

           # Lookup names via DNS first then fall back to /etc/hosts.
           order bind,hosts    (1)
           # We have machines with multiple addresses.
           multi on            (2)
           # Check for IP address spoofing.
           nospoof on          (3)  
The order option indicates the order of services. The sample entry specifies that the resolver library should first consult the name server (DNS) to resolve a name and then check the /etc/hosts file.
The multi option determines whether a host in the /etc/hosts file can have multiple IP addresses multiple interface ethN. Hosts that have more than one IP address are said to be multiomed, because the presence of multiple IP addresses implies that host has several network interfaces.
The nospoof option indicates to take care of not permitting spoofing on this machine. IP-Spoofing is a security exploit that works by tricking computers in a trust relationship that you are someone that you really aren't.