| Quote from: mssystems |
The receiver is perfectly happy passing on signals from different devices transmitting on the same radio channel and goes to the trouble of ensuring that devices transmitting at the same time do not interfere with each other.
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Eh? Don't wireless devices have to avoid transmitting at the same time?
| Quote from: mssystems |
So when two wi-fi devices with the same MAC operate simultaneously, the radio receiver in the access point sorts out any confusion before sending the MAC address onward in electrical form. Two devices transmitting on the same channel with the same MAC just appear as one device to the receiving access point.
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This doesn't quite seem to make sense - how is the access point supposed to sort out the confusion between 2 devices that it thinks are only 1 device? Only one device can transmit at once, if both of the same device transmit at the same time the signals will end up combined and unintelligible. The receiver can't just magically filter out one of the signals - and even if it could, how would it know which one?
I'll answer my own question - regardless of the MAC, the collision avoidance is still done, each radio listens to check the channel is clear before transmitting.
WiFi devices have to authenticate and associate with the access point first - identifying themselves with their MAC address. Then, even if the hypothetical intruder knows the WPA password, they still have to do the WPA key exchange to set up the actual encryption keys - how are 2 devices going to do this at the same time? Wouldn't the 2 devices keep disconnecting the other and re-connecting themselves? When one device is switched off, sending deauthentication and dissassociation packets, the other will need to re-connect.
It is easy to spoof the MAC address
to bypass MAC address restrictions - but I think there will be a lot of confusion with two of the same device trying to transmit at the same time. I suppose the intruder could passively monitor the wireless and then only use it when no-one else is connected.
