I'm using raspberry Pis with raspbian lite for a project that requires them to be out in the streets with a 4G dongle to get internet access. As you can imagine, I want to keep the device's data consumption the lowest possible and doing some research plus some practical experiments (ifconfig data traffic measures) I've found that raspbian alone has around 243 KiB/hr of Rx data and 58 KiB/hr of Tx data. Which is kind of a lot given that i'm sure none of that is being used for my project.
Does anybody have an idea of what the OS is using that data for, and how can I decrease it? I've thought about putting the interface down and only bringing it up when I absolutely need it ( ifconfig "interface" down and ifconfig "interface" up), would that be a good idea?