Hi I've a usb dongle based internet connection from MTS, India in which they provide you a usb modem that can access internet and which also acts as a wifi hotspot through which upto 5 users can access internet simultaneously. (Huawei EC315) Now i'm concerned that some unsavoury people in my neighbourhood could be using it without my knowledge and eating away my data. The modem in concern does not provide anyway of knowing which devices are currently accessing the device and therefore the internet. So my main question is that how can i prevent a device that i had previously once allowed to access my usb wifi modem from accessing it again without my permission? Like there are few people in my neighbourhood that requested me to let them use my internet for awhile and i of course couldn't say no. But those are the same people who i'm concerned could now be using my internet silently and now i want to prevent their devices' access without my permission. Can a guest network be a solution or something else? Preferably what i want is that everytime a device (other than the ones in my home that could freely access my modem) tries to access my modem the modem should ask for a password despite that device having previously accessed the modem.