Squid 3 Installation error

Question

I am trying to install squid using command

sudo apt-get install squid

but I am getting following error --

betgbs@proxy-server:~$ sudo apt-get install squid
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package squid

I also tried to install apache2 and many other softwares but getting same error. Installation is done properly and system is working fine. Please help me out to install squid 3.1.19 on my Ubuntu system. Thank you

Solution

Two issues:

1. It sounds like your package lists are missing a fair number of packages that should be there. This might be a temporary problem that you can fix by running sudo apt-get update (or clicking the Check button in Update Manager), or it might indicate that your package sources are not configured correctly. If it is a problem with package sources, I would suggest picking Settings... from Update Manager and checking the Ubuntu Software and Updates tabs.

2. The squid package contains Squid 2.x. If you want to install Squid 3.x, install the squid3 package instead. If you're running Ubuntu 11.10, this will give you version 3.1.14.