I am an Ubuntu user for the last couple of years. Recently facing problem to connect my new laptop into the Internet. I have an ISP connection which provide me a NAT address.

I changed all the information in network configuration.The network icon shows it is connected to Internet but when I browse, ping shows no Internet connection. /etc/network/interfaces look like this:

auto eth0
iface eth0 inet static
address 192.168.100.118(put you internet address provided by the ISP)
gateway 192.168.100.1(gateway address)
netmask 255.255.255.0
network 192.168.100.0

And when I ping my DNS server IP get the reply from DNS server.

I can not understand the problem,it should be mentioned that I also changed the Physical address of my laptop for using the existing connection.

In windows the connection is working fine.

Any suggestion in this question will help me a lot.

Thanks in advance.