dns cache in debian

nscd -- cache your dns lookup

sudo aptitude install nscd

clean your dns cache

sudo /etc/init.d/nscd restart

(if you don't have nscd, your system will try to look from dns server everytime when you use a host name)

or you can build your own dns server "bind9"

sudo aptitude install bind9

get your global dns server ip address updated:

wget ftp://ftp.internic.net/domain/named.cache

and save to /etc/bin/db.root