Setting up DNS
When it comes to DNS setup Debian doesn’t differ from other distributions. You can add hostname and IP addresses to the file /etc/hosts for static lokups.
To cause your machine to consult with a particular server for name lookups you simply add their addresses to
/etc/resolv.conf.
For example a machine which should perform lookups from the DNS server at IP address 192.168.1.1 would have a resolv.conf file looking like this:
search my.flat
nameserver 4.2.2.2
nameserver 4.2.2.3
(Here the search my.flat causes lookups of hostnames to have my.flat appended to them. So lappy would be looked up as lappy.my.flat)