You can use the -I option to netstat
to display the number of packets sent
and received on an interface in a given time interval.
For example,
the following command displays activity
on the net0 network interface every 5 seconds:
netstat -I net0 5
The output appears similar to the following:
input (net0) output input (Total) output
packets errs packets errs colls packets errs packets errs colls
5533475 276 4615973 460 14899 6063429 276 5145927 460 14899
2 0 1 0 0 2 0 1 0 0
5 0 3 0 0 5 0 3 0 0
21 0 21 0 0 21 0 21 0 0
...
The first row of figures shows the cumulative totals since TCP/IP was last
started. Subsequent rows show statistics collected in the previous five
seconds. The first five columns show numbers of input and output packets,
errors and collisions for the net0 interface. The remaining columns show
the totals for all interfaces including the loopback interface.
Errors indicate packets lost due to hardware problems such as breaks in
the network or faulty adapter hardware. Collisions on an Ethernet
are caused by two or more hosts trying to broadcast at the same time.
This is not normally a problem unless the ratio of collisions to output
packets rises above 10%.