apt-get install bandwidthd

/etc/bandwidthd/bandwidthd.conf

####################################################
# Bandwidthd.conf
# 
# Commented out options are here to provide
# documentation and represent defaults
 
# Subnets to collect statistics on.  Traffic that 
# matches none of these subnets will be ignored.
# Syntax is either IP Subnet Mask or CIDR
#subnet 192.168.0.0/24
 
subnet 6.6.6.0/24
 
 
# Device to listen on
# Bandwidthd listens on the first device it detects
# by default.  Run "bandwidthd -l" for a list of 
# devices. 
#dev "eth0"
 
dev "eth0"
 
###################################################
# Options that don't usually get changed
 
# An interval is 2.5 minutes, this is how many 
# intervals to skip before doing a graphing run
#skip_intervals 0
 
# Graph cutoff is how many k must be transfered by an
# ip before we bother to graph it
#graph_cutoff 1024
 
#Put interface in promiscuous mode to score to traffic
#that may not be routing through the host machine.
promiscuous true
 
#Log data to cdf file htdocs/log.cdf
#output_cdf false
 
output_cdf true
 
#Set the cdf log output directory
#log_dir "/var/lib/bandwidthd"
 
#Read back the cdf file on startup
#recover_cdf false
 
recover_cdf true
 
#Libpcap format filter string used to control what bandwidthd see's
#Please always include "ip" in the string to avoid strange problems
#filter "ip"
 
#Draw Graphs - This default to true to graph the traffic bandwidthd is recording
#Usually set this to false if you only want cdf output or
#you are using the database output option.  Bandwidthd will use very little
#ram and cpu if this is set to false.
#graph true
 
#Set META REFRESH for static pages in seconds(default 150, use 0 to disable).
#meta_refresh 150
 
meta_refresh 150
 
#Set the static html output directory
#htdocs_dir "/var/lib/bandwidthd/htdocs"

service bandwidthd restart