Is there a way to monitor number of bytes being transmitted and received from the Internet? I will be connecting the Yun to a cellular hot spot and need to keep the data usage to a minimum. Does Yun run any background processes that are consuming Internet data? I have installed bmon, but I cannot tell how many bytes are actually going to the Internet.
I'm sure there are some background processes going on: at a minimum there is the NTP client that periodically goes out to get the time and set the clock.
** **ifconfig** **
command reports the bytes received/transmitted on each network interface.
Doesn't your Internet device have a way to determine the number of bytes you've used? I also have a cellular connection as my only Internet access method, and it has a web interface that tells me exactly how much I've used during a billing period, and how much I have left for the month.
I've found that looking at the total bytes sent/received by a computer/device is always higher than what the cellular device reports (and the amount that I am billed.) I chalk this up to traffic between the computer/device and the cellular device that doesn't actually go out over the Internet, things like WiFi association/authentication packets and other local overhead like DHCP leases and periodic renewals, and name resolution requests that are handled by a DNS cache in the Internet device that do not have to go out to the Internet each time. In addition, each packet sent/received has a certain amount of network overhead associated with it - these packets could be combined/split by the cellular device before they go over the air, so the amount of overhead could easily change. There could also be traffic between your Yun and a local computer that will show up in the Yun's traffic totals, but not go out over the Internet, so it won't count towards your cellular bandwidth.
That's just a long way of saying that watching the network counts for your Yun will likely not give you exact information. I've tried watching those numbers from various devices in the past, and got worried that I would go over budget. But the actual amount of data on the cellular bill has always been less.
I installed tcpdump and see calls to ntp every few minutes. I tried modifying /etc/config/ucitrack and then rebooted to have it check every hour, but it is still checking every 20 min or so. I don't really need the clock so once a day is probably fine.
option init ntpclient
option interval 3600