IT Certification

I believe we all foresee such a problem, right? Is that when you in their own local area network (lan) Units 1 to set up an internal Web Server, when someone from the Internet (Wan) can not be a normal visit to Lan’s Web Server you are not very painful? Or you local area network (Lan) NOT to open a computer 80 (Web Server Port) port, but you want others to visit the Web Server Port you when you can with the local area network (Lan) Units 1 has been opened within the Web Server Port of the computer automatically Connect? so this time you will need to use port redirect function (Network Address Translation Nat).
Port redirect (port mapping): If the ISP provide more IP addresses can use the NAT server for each map an external address. But if it is not the time (such as when the two), with the Nets four servers have required foreign corporations to provide services, one for network address translation and one for external network services.