Changing NAT settings

Please follow the steps given below to enable or to disable the NAT function on a modem...

To open the command prompt

Windows XP :- START -> RUN -> cmd (PRESS ENTER)
Windows Vista & Windows 7 :- START -> On the start search type cmd (PRESS ENTER)

Will get a black windows then type

ipconfig (PRESS ENTER)

Now make a note of the DEFAULT GATEWAY (Ex:- 192.168.1.1)

Open the INTERNET EXPLORER and on the address bar type the DEFAULT GATEWAY and then press enter...

You will get the modem user-interface type the user name and password if prompted, you can find it from google if you're not sure about it...
But the default user name will be admin and the password will be password but it depends according to the manufacturer ...

After login to the modem user-interface under the WAN SETUP you can see the option to enable or disable the NAT and DHCP functions...