Tham khảo tài liệu 'configure nat', tài liệu phổ thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Configuring Network Address Translation Two of the key problems facing the Internet are depletion of IP address space and scaling in routing. Network Address Translation NAT is a feature that allows an organization s IP network to appear from the outside to use a different IP address space than what it is actually using. Thus NAT allows an organization with nonglobally routable addresses to connect to the Internet by translating those addresses into a globally routable address space. NAT also allows a more graceful renumbering strategy for organizations that are changing service providers or voluntarily renumbering into classless interdomain routing CIDR blocks. NAT is also described in RFC 1631. For a complete description of the NAT commands in this chapter refer to the Network Address Translation Commands chapter of the Dial Solutions Command Reference. To locate documentation of other commands that appear in this chapter use the command reference master index or search online. NAT Business Applications NAT has several applications. Use it for the following purposes You want to connect to the Internet but not all your hosts have globally unique IP addresses. NAT enables private IP internetworks that use nonregistered IP addresses to connect to the Internet. NAT is configured on the router at the border of a stub domain referred to as the inside network and a public network such as the Internet referred to as the outside network . NAT translates the internal local addresses to globally unique IP addresses before sending packets to the outside network. You must change your internal addresses. Instead of changing them which can be a considerable amount of work you can translate them by using NAT. You want to do basic load sharing of TCP traffic. You can map a single global IP address to many local IP addresses by using the TCP load distribution feature. As a solution to the connectivity problem NAT is practical only when relatively few hosts in a stub domain .
