I installed Ubuntu server 12.04. I configured my network like this:

auto eth0

iface eth0 inet static

address 121.127.36.164

netmask 255.255.255.0

network 121.127.36.0

broadcast 121.127.36.255

gateway 121.127.36.1

dns-nameservers 208.67.222.222 208.67.220.220

with these configurations, I cannot connect to internet.

Whenever I do

ping www.google.com

it just waits. When I do

ping 77.245.149.23

or any other IP, it returns unreachable host error. Could you please help me fix this error?

Edit: I can ping the IP from my network. My modem is set to DHCP enabled dynamic IP.

Edit 2:
Sorry for my late explanations, but I must firstly explain the scenario:

There is a company with 20 staff. I developed a web application with PHP/CodeIgniter for them. Where they want to use it inside their local network.

I install an Ubuntu server 12.04, and want to make it a local server for this purpose. I need to assign a static IP address for this server, where it musnt changed.

I have a TP-Link Wireless Router, where the internet connection is provided through this router. It is DHCP enabled.

Now for this, what I need? How I must configure my server?