I came across this tutorial here that describes how to monitor bandwidth using iptables. I wanted to adapt it for a non-router machine, so I want to know how much data is going in/coming out and not passing through.

Here are the rules I added:

iptables -N ETH0_IN
iptables -N ETH0_OUT
iptables -I INPUT -i eth0 -j ETH0_IN
iptables -I OUTPUT -o eth0 -j ETH0_OUT

And here is a sample of the output:

user@host:/tmp$ sudo iptables -x -vL -n
Chain INPUT (policy ACCEPT 1549 packets, 225723 bytes)
    pkts      bytes target     prot opt in     out     source               destination         
     199    54168 ETH0_IN    all  --  eth0   *       0.0.0.0/0            0.0.0.0/0           

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
    pkts      bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 1417 packets, 178128 bytes)
    pkts      bytes target     prot opt in     out     source               destination         
     201    19597 ETH0_OUT   all  --  *      eth0    0.0.0.0/0            0.0.0.0/0           

Chain ETH0_IN (1 references)
    pkts      bytes target     prot opt in     out     source               destination         

Chain ETH0_OUT (1 references)
    pkts      bytes target     prot opt in     out     source               destination         

As seen above, there are no packet and byte values for ETH0_IN and ETH0_OUT, which is not the same result in the tutorial I referenced.

Is there a mistake that I made somewhere? Thanks for your time.