- Setting up squid proxy server on Ubuntu (Quick Start Guide)

Squid is an internet proxy server that can be used within a network to distribute an internet connection to all the computers within the network. One central computer is connected to the internet through any means such as dial-up, cable modem, ISDN, DSL, or T1, runs squid, and thus acts as the firewall to the internet. Because it is a proxy, it has the capabilities to log all user actions such as the URLs visited. There are many features that can be configured in squid. This guide is meant to be a quick start guide for those who are eager to get squid working and then configure it from there.

You can also install and configure squid as a cache server on the local individual machine for speeding up your internet access.

Install Squid
Open up the terminal and type the following command to install squid:
sudo apt-get install squid

Squid Configuration
Open the squid.conf file for editing using command:
gksudo gedit /etc/squid/squid.conf

Find the http_port tag, By default it reads
# http_port 3128

This is the default port that Squid will listen on for requests. If you want to change it, uncomment the line and set the correct port. If you want Squid to listen only on one specific NIC, you can also change the IP address – for example : 192.168.1.5:3128

Next, find the http_access section Uncomment these 2 lines:
acl our_networks src 192.168.1.0/24 192.168.2.0/24
http_access allow our_networks

NOTE: You'll need to change 192.168.1.0/24 to match your network. Unless you have a second subnet you can delete 192.168.2.0/24

With above change, the basic squid configuration is done, you can now start/stop the squid server using command: sudo /etc/init.d/squid start|restart|stop

Configuring squid Clients
To configure any application including a web browser to use squid, modify the proxy setting with the IP address of the squid server and the port number that you have specified in the squid configuration file (default 3128).

Below example showing the Firefox configuration for using squid proxy server running on ip address 192.168.1.2 and port 3128.

source:http://linuxpoison.blogspot.com/2010/10/135781677516596.html