TRENDnet TW-H6W1IR manual NAT Configuration

TW-H6W1IR ISDN Remote Router

NAT Configuration

Network Address Translation (NAT) is a routing protocol that allows your network to become a private network that is isolated from, yet connected to the Internet. It does this by changing the IP address of packets from a global IP address usable on the Internet to a local IP address usable on your private network (but not on the Internet) and vice-versa.

NAT has two major benefits. First, NAT allows many users to access the Internet using a small number or even a single global IP address. This can greatly reduce the costs associated with Internet access and also helps alleviate the current shortage of Internet IP addresses. Secondly, the NAT process provides some security found in a firewall, hiding your local network from Internet users, providing a degree of security to your Internet connection.

To be successfully implemented, NAT should be used only when the majority of network traffic remains on the local network. In cases where a large percentage of network traffic is destined for the Internet, NAT can adversely affect the speed and performance of your Internet connection. Also, your network servers such as ftp servers, web servers or mail servers will probably need to be assigned static NAT IP addresses so their IP addresses remain consistent. This issue will be further discussed later.

Network Address Port Translation (NAPT) is a subset of NAT where many local IP addresses and their TCP/UDP port numbers are translated to a single global IP address and it’s TCP/UDP port number. In this document, the term NAT will refer to both NAT and NAPT unless otherwise stated.

76 Configuration and

Management