Monitor network traffic volume over interface

Question

Is there a way to monitor the traffic (e.g., get a live view of the utilization) over a particular network interface, say eth0?

The catch here is that the set of tools on the box is fixed, and is pretty much a stock RHEL deployment, so add-on tools can't be used.

Looking for something basic and usually present like iostat here.

Answer 1

The data you want to see shows up in good old ifconfig.

watch ifconfig eth0

or to make things stand out better:

watch -n 1 -d ifconfig eth0

Answer 2

I use iftop command. It shows statistics in realtime.

iftop -i eth0

Checkout some sceenshots here:

http://www.thegeekstuff.com/2008/12/iftop-guide-display-network-interface-bandwidth-usage-on-linux/

Answer 3

Take a look at NTop. It provides a lot of detailed data.

Answer 4

There are a lot of utilities:

1. Nethogs
2. iptraf
3. Iptables can be a good solution to but if you are using a firewall set up will be a bit hard to relocate correctly the rules

Answer 5

You can also use iptables to do such think:

iptables -A INPUT -p tcp --dport $port -i eth0

and

iptables -A OUTPUT -p tcp --sport $port -i eth0

Then iptables -L -n -v will print you how many packets have been going through the interface, iptables -Z to zero this count