If you get an error about not being able to resolve the host, you need to edit your /etc/resolv.conf and add proper resolvers. For servers in our network, the following command will suffice. If you are not in out datacenter, you will need to find out your host's DNS info:
echo -e "nameserver 213.133.98.98" >> /etc/resolv.conf
echo -e "nameserver 213.133.99.99" >> /etc/resolv.conf