How can I tell if my computer's WIFI connection is actually going through a router and not tethering through somebodies mobile phone?
I assume you mean through your router. The easiest way is to log into your router and check that the MAC address of your device is showing up as a client. Rogue APs are a real concern, and anyone with their own router or mobile phone could setup a network using the same SSID and password as the legitimate network in the building, and your device will connect to the strongest signal, however phones have weak range so the likely hood of you connecting to someones phone is rather slim if you are near a legitimate AP. After you connect, you can check your IP details and see what you were given via DHCP. Generally phones give out standard 192.168 addresses, and they will be the gateway and DNS server, whereas a corporate network would usually have a different network addressing scheme and would have different gateways and DNS servers. You can also use wireless analyzing software to see the vendor and signal strength of networks around you, often it will tell you the name of the phone or phone manufacturer if it's a phone hotspot.
Also, if somebody was given out a false Wifi connection from their mobile phone how easy is it to intersect somebodies connection? I heard from a BT engineer that internet connections are encrypted anyway?? At what stage do they become encrypted if that was the case?
Most internet traffic that passes confidential data like user passwords, banking information, etc. uses HTTPS and is encrypted, however lots of general web traffic, and unsecured protocols like telnet, ftp, etc. are now and passwords are sent in clear text.
What your describing is not needed, as there doesn't need to be a "middleman" in a WiFi network to see your traffic. Anyone can be within range of your device and see traffic that is being passed by your device, and anything unencrypted is visible. When you connect to a secured wireless network however, all your traffic is encrypted from those on the outside.
That answer is really simple. What network name does it show you are connected to?
I wouldn't use that as a deciding factor, if you had a network called John123 I could create my own network called John123 and try to get you to join mine instead.
Any wireless giving off from a cell phone is password protected and you would have to know that password to connect to it.
By default, yes, but this can be disabled.
The router encrypts the wireless signal.
If it's using WPA/WPA2 it is, if it's an open network it does not.
Depends on the security you have set up. If you just have an open SSID then anyone can just roll one with whatever similar name to yours. If you are using WPA2, for example, the spoofer wouldnt be able to set up their own named as your SSID unless they already knew the passphrase, otherwise your PC would see the ssid name but the security wouldn't match.
This is correct. And OP, if someone does know the name and password of a network you connect to, such as your home or work, there really isn't much reason for them to go through all this trouble. If they are in range for you to connect to their device, they are already in range to see traffic you're sending. They can use a packet sniffer and filter it based on your MAC, there really isn't a need to have you connect to their rogue AP, as most likely once you do things like shared drives, printers, etc won't work and you'd expect something was up and start troubleshooting.
