Linux Display Bandwidth Usage on Network Interface By Host

by on April 19, 2006 · 7 comments· LAST UPDATED November 25, 2013

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The iftop command listens to network traffic on a named network interface, or on the first interface it can find which looks like an external interface if none is specified, and displays a table of current bandwidth usage by pairs of hosts. iftop is a perfect tool for remote Linux server over ssh session.

iftop must be run by the root or the user who has sufficient permissions to monitor all network traffic on the network interface. See how to install iftop on CentOS/RHEL based server.

Type iftop command at the shell prompt to display traffic:
# iftop
Sample outputs:

However, iftop works best when you use filters. For example, if you want to find out how much bandwidth users are wasting or trying to figure out why the network is slow,
# iftop -f icmp

You can display or analyses packet flowing in and out of the 192.168.1.0/24 network:
# iftop -F 192.168.1.0/24

Disable output for DNS traffic by using filter code such as:
# iftop -f 'not port domain'

iftop has many options read man page for further information see its man page - iftop(8)

See also:
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{ 7 comments… read them below or add one }

1 Anonymous September 7, 2006 at 1:11 pm

It is a very useful program. This commando shows I deal and the port of a single IP

iftop -P -i any -F 62.165.165.245/32

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2 Artem Nosulchik October 19, 2007 at 11:32 am

It’s also possible to apply filter when iftop is already running: just press “f” button and type filter you wish like:
Net filter> host 192.168.0.7

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3 ahmbay August 29, 2009 at 9:36 am

this is very usefull program. Thanks..

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4 alfin September 10, 2009 at 8:33 pm

thanks, its great
but i still have one question, can iftop change source ip (ex: 192.168.1.2 at picture above) to hostname from each pc that connected?

regrads,..

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5 Penton October 14, 2009 at 4:50 am

marvellous! This application is so useful. I didn’t expect it be to user friendly. :)

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6 blogger February 13, 2012 at 1:44 am

thanks, it works great with my wireless nic.

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7 Pluto April 17, 2014 at 4:49 am

Something that works well via command line (especially for SSH) is iptraf. That lets you view stats with a wide variety of detail. Probably doesn’t work as well as this, but it works well enough ;)

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