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.

Have a look at http://stackoverflow.com/questions/596590/how-can-i-get-the-current-network-interface-throughput-statistics-on-linux-unix. Some of the suggestions on there should be useful. — Andy Smith, Dec 02 '11 at 01:15
D'oh, search fail (and I tried). To be fair, I think it's a serverfault question, not a SO one :) — BeeOnRope, Dec 02 '11 at 22:41

score 23 · Accepted Answer · edited Dec 02 '11 at 19:04

23

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

edited Dec 02 '11 at 19:04

thinice

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answered Dec 02 '11 at 02:39

Joel K

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Thanks - this in addition to the comment by @user239558 was just right. I'm accepting your answer since you were the first to mention `ifconfig`. – BeeOnRope Jan 22 '16 at 00:28
Spot on. This is something I've been looking for and although there are many similar questions to this on different forums, this is the first answer I found that nails it. – Hazok Jun 09 '16 at 18:34
ifconfig is not in the default path. /sbin/ifconfig may be required. – Kevin Apr 06 '18 at 21:22

score 19 · Answer 2 · answered Dec 07 '11 at 22:26

19

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/

answered Dec 07 '11 at 22:26

Awi

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Looks great, unfortunately I am not able to install any new tools on these locked down boxes. – BeeOnRope Dec 15 '11 at 03:19

score 7 · Answer 3 · answered Jan 24 '18 at 17:27

7

on post-2015 or so linux this might be better watch -n1 -d ip -s link show [interface]

answered Jan 24 '18 at 17:27

massemanet

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Best answer today. You can also use `-h[uman-readable]` with `ip` – siikamiika Jul 01 '21 at 20:42

score 4 · Answer 4 · answered Jan 26 '15 at 15:35

4

Without installing new tools:

while ifconfig eth0 | grep 'RX bytes'; do sleep 10; done

answered Jan 26 '15 at 15:35

user239558

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score 4 · Answer 5 · answered May 29 '18 at 16:32

function humanValue()
{
    h=( '' K M G T P )
    i=1; v=$(( $1 * 8 ))
    while [ $v -gt $(( 1 << 10 * i )) ]; do let i++; done;
    echo -n "$(( $v >> 10 * --i )) ${h[i]}b/s";
}
ifaces=$(ip addr | grep -E "^[0-9]:" | cut -d" " -f2 | tr -d \:)
declare -A RX2 TX2;
while sleep 1; 
do
    date 
    for INTERFACE in $ifaces;
    do
        RX1=$(cat /sys/class/net/${INTERFACE}/statistics/rx_bytes)
        TX1=$(cat /sys/class/net/${INTERFACE}/statistics/tx_bytes)
        DOWN=$(( RX1 - RX2[$INTERFACE] ))
        UP=$(( TX1 - TX2[$INTERFACE] ))
        RX2[$INTERFACE]=$RX1; TX2[$INTERFACE]=$TX1
        echo -e "[ $INTERFACE:\tRX: $(humanValue $DOWN)\t|\tTX: $(humanValue $UP) ]"
    done;
done;

score 2 · Answer 6 · edited Dec 02 '11 at 14:20

2

There are a lot of utilities:

Nethogs
iptraf
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

edited Dec 02 '11 at 14:20

quanta

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answered Dec 02 '11 at 02:36

dSoultanis

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iptraf is exactly what i was looking for. But its last release seems be in IPTraf 3.0.0 - September 19, 2005. can this be a problem? – Al-Alamin Apr 25 '18 at 09:42

score 2 · Answer 7 · answered Dec 02 '11 at 19:19

2

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

answered Dec 02 '11 at 19:19

philippe

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Output chain should have -o as interface, -i is illegal – Drakarah Apr 29 '19 at 07:38

score 1 · Answer 8 · edited Jul 20 '12 at 18:23

1

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

edited Jul 20 '12 at 18:23

Lucas Kauffman

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answered Dec 02 '11 at 13:56

Nicholas

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score 0 · Answer 9 · edited Aug 06 '22 at 15:20

0

You can use

netstat -w8 -h -i eth0

Which will display bits/sand in/out. -w8 Waits 8 seconds, -h converts output to humand readable numbers. Works in Linux/FreeBSD.

edited Aug 06 '22 at 15:20

bjoster

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answered Jul 30 '22 at 18:36

Asif.Eppyhatman

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Monitor network traffic volume over interface

9 Answers9