Routers

A router acts as a means of connecting a cable/DSL high speed broadband connection to your network.  When you have a router, you do not need more than one IP address, because all internet traffic flows through the router.  Most Routers use NAT (Network Address Translation) to take the request from your computer and send it out over the internet.  NAT provides a level of protection because your computer is not visible to the outside world, only the router is.  Some routers also have a built-in firewall, which adds another level of protection fending off hidden attacks to your computer.  Routers can also come with built-in hubs, which make it real compact and easy.

Software based routers are available and act the same way as the hardware based versions do.  With a software based router, you connect two network cards to a computer.  One of these network cards is connected directly to your cable/DSL connection.  The other card is connected to your network.  All internet traffic flows through this computer.  The software can sometimes be found as freeware, so this might be a cheaper option.  Remember, you need to leave this "router" computer on all the time.

If you want people to be able to access a computer inside the network (games, web server, etc.) you simply have to go into the router's configuration console and open up the ports that you need.