You need to determine how much money you want to throw at this type of problem. That dollar amount can and will translate to the number of hours spent building and reconfiguring your network structure, the hardware necessary, etc.
Why?
Well, the previous answer didn't address the impossible logistics involved with just plopping some mysterious computer between EVERY connection running out of your router or switch. If he meant that you should install a single monitoring computer for EVERY user, that could get quite expensive. If he meant that you only need install one monitoring computer... then it could need 30 or more network cards installed in it, depending on how many employee machines you have. You didn't make mention of that. However, the previous answer did mention a company name. Untangle.com
One solution that Untangle does offer, is an Untangle Appliance. As you can see, they are not cheap, but they combine a router/switch with a computer. This appliance takes the incoming internet connection at one end, and at the other it connects to all your employee machines (Via network switches, etc). It allows you to monitor, control, filter... actually the controls they offer are quite robust. So is their pricing. But, if you want a premade device and software package you can just drop in... that's an answer.
Otherwise, you would need to examine how your network is currently set up. If you just have a commercial internet connection and modem... and that is connected to a commercial (or residential grade) router/switch... and that is connected to 5 or 6 (or 10, or 16) employee machines... well, you might want to actually set up a domain. I don't mean that you need to go purchase a domain name, but I do mean that maybe you need to set up an actual server to replace the router in this setup. In this case, you would end up with...
Internet --> Server --> Switch --> Users
... as opposed to
Internet --> Router --> Switch --> Users
The server would handle all routing. It would be an actual computer that you could log into, and among other things, allow you to monitor the network traffic, where people are going, set up QoS rules, etc. No different really than one of the security appliances that were already mentioned... EXCEPT... you most likely won't be looking at a monthly or yearly fee, and the price should be much cheaper. You might even be able to recycle some old hardware and set up a Linux machine to do the job.
If you are feeling the need to start monitoring reports on how your employees are using your internet... and you need to do it after the fact... and you can't be watching over their shoulders... it might even be time for hiring a server administrator.
Just a thought.
What exactly are you asking for? Time spent browsing (to see if they're goofing off)? Bandwidth consumption (to see if you have enough bandwidth for your employees)? Specific addresses to know what they're looking at (efficiency)? What people are downloading (security)? Several different ways to look at it. – Brian Daniels – 2013-03-11T14:31:36.780
Size of internet used in MB or GB for specific pc with date – IT researcher – 2013-03-12T10:49:52.840
If you sit a box running untangle between the router and the users in bridge mode. You can configure it to do what you are looking for. Here's a link to the site: http://www.untangle.com/
– Simkill – 2013-03-11T14:51:48.617