1. install squid
sudo apt-get install -y squid
sudo update-rc.d squid3 defaults
2. configure squid
sudo gedit /etc/squid3/squid.conf
3. change config
cache_peer 10.1.2.3 parent 80 0 no-query default login=my_username:my_password
never_direct allow all
4. restart
sudo /etc/init.d/squid3 restart