NAT- network address translation
NAT hides internal IP addresses by converting private network addresses (Intranet) into public addresses (such as the Internet). In this way, by using unregistered IP addresses internally and converting them into a small number of externally registered IP addresses, the cost of IP address registration is reduced and the increasingly scarce address space (namely IPV4) is saved. At the same time, it also hides the internal network structure, thus reducing the risk of internal network attacks.
Three types of NAT
There are three types of NAT (static NAT, pooled NAT and port NAT).
1, in which the static NAT setting is the simplest, and each host in the internal network is permanently mapped to a legal address in the external network, which is mostly used for servers.
2, and NAT pool defines a series of legal addresses in the external network, which are mapped to the internal network through dynamic allocation, and are mostly used for workstations in the network.
3. PAT maps the internal address to different ports of an IP address of the external network.
Taking static NAT as an example, the configuration steps are as follows:
Suppose there is only one external address, such as 6 1. 177.0.7.
The internal IP is a private address. For example, if the router is set to 10.0. 1, the following computers will be set to 10.0.0.2 to10.0.254.
Take the most commonly used port 80 as an example, set up a virtual HTTP server, and assume that the IP address of the internal HTTP server is 10.0. 10.
Step 1: enter HTTP:/10.0.0.1in the browser to enter other configuration pages and modify the http service port of the router itself. Closing is not recommended, because the HTTP server port is usually changed to 8 1 using the WEB settings.
Submit and restart.
Step 2, open the router control page http:/10.0.0.1:81.
Enter the virtual server page and fill in the public port number 80, private port number 80, port type TCP, and host IP address 10.0. 10.
Click "Add this setting" when finished, then save and restart the router, and the setting is complete. At this point, enter the IP address of the external network in IE, and the external network can access the internal 10.0.0. 10. Of course, the HTTP service should be opened at 10.0. 10.