A router is a multi-function item that sits between you and the rest of the world. It has several names. It can be called a DSL router, a hardware firewall, some people even mistake it for a switch.

A router has several functions.
1. It allows or disallows access to machines behind it.

For instance, if you want to have one machine that has a webserver on it to be able to respond to requests from the internet, you would open up port 80 on your router and “redirect” any requests sent to port 80 to the specific machine that has the webserver. How you would do this depends on which router you have.

Most users will use it to make sure that traffic from the Internet cannot reach them, except for that which they request. For example, if I ask for [link] , the router will pass the information sent from that website back to my computer. If a malicious person were to try to connect to a “port” on my computer, such as port 25 ( commonly a port used for an email server ) the router would deny access to that person.

2. It can filter what sorts of access certain users behind the router have to the internet.

This can be based on the time of day, the type of sites, or even ( on some routers ) based on the user.

For instance, if I notice that one user in the house is spending too much time on the internet, and not getting their important tasks done, I can deny them access to the internet before say 9pm. Or, if I know that the website they are always on, is for instance motodrive.com, I can enter this into the router’s settings as being a “banned site”.

3. It can allow many machines in the house or office to share internet access.

At first, this might seem like it would be something that would upset your Internet Service Provider. Not true. They realise that many households today have more than one computer. It’s even the reason that they offer you more than one “IP address” per account. The only caveat to this, is that if you need their help troubleshooting, they will likely have you connect directly to the modem, in order to ease the troubleshooting, and to rule out the router as the culprit.

4. It can help you to share printers and other devices, so that everyone can use them, and so that for instance, you don’t have to buy a printer for every user.