One interesting application that is used to monitor the network on Ubuntu or other is GNU\linux EtherApe which shows details of the traffic and nodes that are connected with us in our network with a graphic display showing the rate of the traffic and the connected nodes.
The first thing to do is install EtherApe on Linux you, I happen to use Ubuntu, who used the distro besides ubuntu and debian derivatives can be downloaded here. Open a terminal type.
sudo apt-get install etherape
The application can be the way in root mode so on terminal type
To monitor interfaces which will be on the menu on the monitor Captute > Interface – where select interface, example= eth0 or wlan0 or ppp0 for dial-up modem. Or for quickly opening applications etherape and want to monitor through terminal type woreless network.
sudo etherape -i wlan0
And to see the details of the traffic in the form of numeric tables select the menu View – > Protokols/Nodes