To keep track of the internet traffic my family is causing, I wrote a little perl script that runs on the Soekris and displays the output of ipfstat. This works because ipf is able to count traffic by using rules such as:
count in on sis0 all
coun out on sis0 all
The perl script just parses the output of ipfstat -noia and displays it in a more or less fancy way. You may find the script among other things in the Soekris directory on my homepage.
Perhaps this is of some interest to other Soekris owners.