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.

Solution 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

Solution 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/

Solution 3

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

Solution 4

Without installing new tools:

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

Solution 5

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;

View more solutions

Comments

[Andy Smith]

Have a look at stackoverflow.com/questions/596590/…. Some of the suggestions on there should be useful.

[BeeOnRope]

D'oh, search fail (and I tried). To be fair, I think it's a serverfault question, not a SO one :)

[BeeOnRope]

Looks great, unfortunately I am not able to install any new tools on these locked down boxes.

[BeeOnRope]

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.

[Hazok]

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.

[Kevin]

ifconfig is not in the default path. /sbin/ifconfig may be required.

[Al-Alamin]

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?

[Drakarah]

Output chain should have -o as interface, -i is illegal

[siikamiika]

Best answer today. You can also use -h[uman-readable] with ip