NetHogs is a small network monitoring tool. Instead of breaking the traffic down per protocol or per subnet, like most tools do, it groups bandwidth by process. NetHogs does not rely on a special kernel module to be loaded. If there's suddenly a lot of network traffic, you can fire up NetHogs and immediately see which process is causing this. This makes it easy to indentify programs that have gone wild and are suddenly taking up your bandwidth.
To install NetHogs under CentOS, Fedora, RHEL, enter:
yum install nethogs
To install NetHogs under Debian and Ubuntu, enter:
apt-get install nethogs
The default network interface to monitor is eth0. If you wish to use other device, simply type the argument after nethog, open the terminal and run the following command:
usage: nethogs [-V] [-b] [-d seconds] [-t] [-p] [device [device [device ...]]]
-V : prints version.
-d : delay for update refresh rate in seconds. default is 1.
-t : tracemode.
-b : bughunt mode - implies tracemode.
-p : sniff in promiscious mode (not recommended).
device : device(s) to monitor. default is eth0
When nethogs is running, press:
m: switch between total and kb/s mode