Polipo is a Linux proxy, like squid but it is intended in a personal use, I used to use squid as my personal proxy but because I have a PIV HT processor and 1 Gig of RAM, in Laptop that approach was just to heavy for it.
Now with Polipo things will change, well go to the installation.
apt-get install polipo
There is almost no need to change the configuration file as with the defaults it will work great as a personal firewall.
But if you are configuring it as you home proxy, you can change these lines on the file /etc/polipo/config
proxyAddress = "0.0.0.0" # IPv4 only allowedClients = 127.0.0.1, 192.168.42.0/24
be sure to change 192.168.42.0/24 for your own IP address range, in general no further changes are needed.
Go to Edit->Preferences->
On this screen:
Select Advanced and then click on setting, then:
Select "Manual proxy configuration" and enter the IP of the PC where polipo is installed and enter the port which is: 8123
Go to Desktop->preferences->Network Proxy
And Select "Manual Proxy Configuration" and also here enter the IP of the PC where Polipo installed and the port 8123
Go to Tools->preferences, and once on this screen
Now select Advance and click on Network and then on Proxy Servers.
And once again enter the IP and port of your polipo server.
As a final step you can configure your apt if you are using Debian or Ubuntu, I always do, that way my Laptop gets its updated really fast as usually my Desktop have already downloaded them.
Apt Configuration to work with proxy
And add this line
be sure to change the IP to the one that corresponds to your Polipo server.