Resolv.conf

When you boot your system it tries to use your ISP's DHCP server to obtain it's public routable IP address from your ISP, in addition the ISP will give you it's DSN domain name and nameserver IP address which automaticaly replaces the contents in the /etc/resolv.conf file. In most cases you never change what your ISP gives you.

The following is for advaniced users with large local area networks.

The format is:

domain freebsdwiki.net
nameserver 169.254.1.1
nameserver 172.16.1.1 

To attempt to resolve incompletely qualified hostnames using more than one domain name if necessary, use:

 search freebsdwiki.net somethingelse.com anotherdomain.org

In plain english, that line means that if you try to ping webserver from the shell, your machine will try to resolve webserver.freebsdwiki.net, webserver.somethingelse.com, and webserver.anotherdomain.org before giving up.

Be careful with this, you really don't want to have every attempt at a DNS resolution take 15 seconds or more to time out because you have to contact tons of different nameservers due to your "search" string. There is also a pretty obvious potential for namespace overlap and confusion, ie if you have distinct hosts named webserver, fileserver, or printserver (or whatever) in more than one of your search domains.