Cisco router NAT Translation

Cisco router nat translation 1. One-to-one correspondence between the internal address and the egress address disadvantages: When the egress address resources are scarce, only a small number of hosts can be connected to the internet. 2. The internal address shares the egress address. The router uses the egress address and port number, as well as the external host address and port number as the interface. The internal address port number is a random number greater than 1024, and the external host port number is recognized as a standard port number. In this way, you can use the same egress address to allocate different port numbers to connect any number of internal hosts to the Internet. Specific configuration of www.2cto.com: Because the experiment uses ISDN to dial up the internet, only the egress address can be obtained randomly on the internet, so the address pool for NAT translation is set to the address obtained by dialing on the BRI port. Interface FastEthernet0/0 ip address 172.16.18.200 255.255.255.0 ip nat inside the interface connected to inside world! Interface BRI0/0 ip address negotiated ip nat outside the interface connected to outside network encapsulation ppp no ip split-horizon dialer string 163 dialer load-threshold 150 inbound dialer-group 1 isdn switch-type basic-net3 ip nat inside source list 1 interface BRI0/0 overload access-list 1 permit 172.16.18.0 0.0.255 www.2cto.com 3. Internal and external addresses overlap when internal and external addresses use the same network segment address, if the addresses are not repeated, you can perform NAT forwarding for both internal and external interfaces. To enable normal communication. 4. Use an egress address to map multiple internal hosts to a large website on the internet. Multiple hosts correspond to the same egress address of the same system. You can use the sh ip nat translation and debug ip nat commands to check the NAT status.