Today i tried to run nslookup on a Ubuntu VPS

root@cloud1:~# nslookup
-bash: nslookup: command not found
root@cloud1:~#

It was Ubuntu 12.10

root@cloud1:~# cat /etc/*issue
Ubuntu 12.10 \n \l

root@cloud1:~#

To find which package provides nslookup command, use apt-cache search

root@cloud1:~# apt-cache search nslookup
dnsutils - Clients provided with BIND
libnet-nslookup-perl - simple DNS lookup module for perl
root@cloud1:~#

We found 2 packages that is related to nslookup. First one is what we need. Second one is related to Perl, that is for Perl Programmer.

So we install dnsutils

apt-get install dnsutils