Fierce domain scan was born out of personal frustration after performing a web application security audit. It is traditionally very difficult to discover large swaths of a corporate network that is non-contiguous. It's terribly easy to run a scanner against an IP range, but if the IP ranges are nowhere near one another you can miss huge chunks of networks.
Step 1 :
sudo apt-get install libnet-dns*
sudo -sH
mkdir /opt/fierce
cd /opt/fierce
wget http://ha.ckers.org/fierce/fierce.pl
wget http://ha.ckers.org/fierce/hosts.txt
Step 2 :
sudo -sH
cd /opt/fierce
perl fierce.pl -dns samiux.com -wordlist hosts.txt -file output.txt
That's all! See you.