Thread: How To: Monitor and log network traffic [Linux Only]

What?
The program is called vnStat and is a console based bandwidth monitoring tool. It doesn't take a look at what sites are being viewed or anything like that. All it does is take a look at
internet traffic information that the kernel provides and logs it in a retrievable, readable format.

Why?
Knowing how much bandwidth you use can be both really useful and really interesting at the same time!

How?
Note: I am a user of #!Crunchbang, a Ubuntu based distro which in turn is based on Debian. As such, I will be using apt-get, but for other major distros, simply use the distro package manager (Arch: pacman, etc...)
1) Login as root in a terminal

Code:

su -i

2) Install vnStat

Code:

apt-get install vnstat

3) Find the names of the network interfaces you'd like to monitor
*The usual names are eth0 or eth1 for Ethernet and wlan0 for wireless

Code:

ifconfig -s

4) For each interface you'd like to monitor, type this in (where **** stands for the name of the interface)

Code:

vnstat -u -i ****

5) Congratulations! Installation is complete. Now all that's left to do is do some internet surfing (or downloading) and check back later.
To check out the data that vnStat has collected, in a terminal, type:

Code:

vnstat

to get a basic readout. To get some more information out of it, type:

Code:

vnstat --hours

for a graph that shows hourly usage. Be sure to check man vnstat for many other options, including a daily view, weekly view, and even monthly!

A Little Extra:
For those of you who want some more out of this program, there are several frontends available, however I highly recommend this one that was made in PHP: vnStat PHP frontend