If you want to monitor bandwidth of your Linux server , here are some awesome tools for monitoring network bandwidth . some of these tools allow monitoring on process level so you can actually see which app is eating bandwidth .

1 . Bmon

bmon – bandwidth monitor and rate estimator , its awesome tool for monitoring multiple interfaces of network in single terminal .

2 . nethogs

nethogs – Net top tool grouping bandwidth per process , you can use nethogs to monitor per process network activity .

3 . Slurm

slurm is a generic network load monitor which shows device statistics together with a nice ascii graph. Three different types of graphs are supported

4 . Ifstat

its show stats of all interface at once , you can pass -tz to print timestamps and filter null interfaces

5 . speedometer

speedometer – measure and display the rate of data across a network connection , just pass -b -t -r eth1 where eth is your interface , to see something like this

6 . iftop

iftop – display bandwidth usage on an interface by host .

7 . iptraf

Its pretty much useless if you are trying to use this on your desktop or laptop for monitoring wireless lan connection because wireless interface is not supported . works good with Ethernet .

8 . trcptrack

its like top for network monitoring .
according to man pages

” tcptrack displays the status of TCP connections that it sees on a given network inter‐
face. tcptrack monitors their state and displays information such as state, source/des‐
tination addresses and bandwidth usage in a sorted, updated list very much like the
top(1) command.
”

9 . nload

nload – displays the current network usage