andersonec":w5uewgg0 said:
I was under the impression that if you had your wifi system up and running people could park up outside your house and get all the information they needed off your computer, passwords, bank details etc, now I am reading, what sounds to me like your router is part of one big network that any passer by can use to access the internet, is this really the case?
Any computer network is just a number of devices (e.g. computers) connected together by cables, wifi, satellite links, whatever - much like the telephone network, in fact. And also like the telephone network, to talk to a particular computer you need to know its number (IP address) and when you try to connect to that number, a lot of switching equipment between you and them routes your conversation (network connection) along the appropriate channels - be they wires, WiFi connections, satellite links or whatever.
Leaving your WiFi open to everyone all the time is a bit like leaving one of the handsets of your multi-handset house phone in the front garden - anyone can walk by and pick it up and use it to call their mate, who may or may not live in Australia. Luckily you get charged only for the amount of data that passes back and forth and not for which country it goes to or from, and there's no such thing (yet!) as a premium-rate internet address, but if you're on a limited-data plan with your internet connection company then they're using up your data allowance as surely as the guy picking up the phone handset would be using up your phone talk-time.
Similarly, if you were already on the telephone talking dirty to your mistress (e.g. sending an email over the WiFi connection), someone picking up the handset in the garden may be able to listen in to the call without you knowing about it - it's not impossible depending on how the router is set up to eavesdrop on WiFi communications - and then blackmail you with the details later. That's one reason it's always important to use secure connections to banking or retail websites when putting passwords or card details in - make sure there's a padlock in the address bar of your browser, 'cause that encrypts the conversation and anyone eavesdropping won't be able to make head nor tail of the conversation.
Because you may have multiple devices in your home - a desktop, a laptop, the WiFi access point, the Internet router - it's like an office full of guys all with their own dedicated extension. The guy with the handset in the garden can call any of the other extensions in the office and it'll come through as an internal call - he'll literally be on your local home network, not coming in over the public internet - and depending on how your security software/operating system is set up, that may mean he can access things on your computer that he shouldn't be able to. In the same way as a secretary in an office is more likely to give out people's diary information to a caller on an internal line than someone who calls from outside the office!
I wouldn't worry
too much about people being able to access your computer from the WiFi connection - it's technically possible, but unless you shared files deliberately with your home network, or use your credit card over an unsecured connection (no padlock in the address bar) you're largely OK. Most computers don't actually allow anyone on the local network to just waltz in and take what they like! Just bear in mind that anything another computer in the house can access, a guy parked up outside coming in over the WiFi can probably also access, and you'll generally be fine.
It's a much larger risk IMO that people may park up outside and use your internet connection, and if they do anything illegal with it, you're the one most likely to get in trouble, at least at first! So it's worth restricting access to the WiFi if your router allows it - MAC filtering and WPA2 are both worth enabling if your WiFi access point supports them. Obviously the safest answer is to turn the WiFi off entirely, or turn it off when you're not using it!
