Setup the Quota for internet User.

Using a Simple iptables command we can set up a quota for the internet user

Step 1
Take a Linux machine which will act as a gateway for you and route all the traffic from

All we want to have is the following: packets arriving from the local net with a receipient's IP address somewhere in the internet have to be modified such that the sender's address is equal to the router's address. For further command examples let us assume that the first interface 'eth0' is connected to the local net and that the router is connected to the internet via the second interface 'eth1'. The command for a shared internet connection then simply is:

# Connect a LAN to the internet gt; 
iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE

#Lets say we have a user for which i have to set a bandwidth of  13 GB/month 
iptables -A INPUT -p tcp -s 192.168.0.2 -m quota --quota 13958643712 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 80 -j DROP
or
iptables -A INPUT -p tcp -j CLASSIFY --set-class 1:12

So in the above rule will allow the user (192.168.0.2)  to user the internet service up to 13 GB

after a month you need to fire
iptables -F
 and run the above command again or even you can schedule a cron job for this .and we are all set the Shell script will look like this.


#!/bin/bash
 # step 1
iptables -F

# Step 2
# Connect a LAN to the internet gt; 
iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE

 #Step 3
#Lets say we have a user for which i have to set a bandwidth of  13 GB/month 
iptables -A INPUT -p tcp -s 192.168.0.2 -m quota --quota 13958643712 -j ACCEPT

 #Step 4
iptables -A OUTPUT -p tcp --dport 80 -j DROP
or
iptables -A INPUT -p tcp -j CLASSIFY --set-class 1:12
#
#choose one from step 4 as per your requirement
#
#Create a shell script name quota.sh

chmod 777 quota.sh

crontab -e

*        *        1        *        *       /bin/bash  /path to/quota.sh

then save the cron by following keys 'esc' then ': wq'

and we are ready to go.