An enhanced version of the original wrtbwmon. This version allows to define a netmask which is counted as internal traffic. Also a nice web frontend was added using google chart tools to display the traffic data.
https://gitorious.org/wrtbwmon
A router running DD-WRT or the like with Optware (might work without) installed.
Download the script to /opt/bin and make it executable:
$ wget http://gitorious.org/wrtbwmon/wrtbwmon/blobs/raw/master/wrtbwmon -O /opt/bin/wrtbwmon
$ chmod +x /opt/bin/wrtbwmon
Optionally create a /opt/etc/wrtbwmon.rc to override default settings, i.e.
INTERNAL_NETMASK=192.168.0.0/24
Accounting for multiple LAN interfaces is supported you just need to list them in LAN_IFACEs variable in /opt/etc/wrtbwmon.rc i.e.
LAN_IFACEs="br0 br1 br2"
Where br0, br1 and br2 are LAN interfaces. If not specified accounting information will be collected for default LAN interface returned by nvram get lan_ifname.
Call script with 'setup' and 'download_scripts' parameters:
$ /opt/bin/wrtbwmon setup
$ /opt/bin/wrtbwmon download_scripts
Add the following cron jobs:
* * * * * root /opt/bin/wrtbwmon setup traffic
* * * * * root /opt/bin/wrtbwmon update traffic
1 * * * * root /opt/bin/wrtbwmon backup traffic
1 * * * * root /opt/bin/wrtbwmon publish_users traffic