WAN Access Technology-NAT Intranet and external network address translation (1)

WAN Access Technology-NAT Intranet and external network address translation (1)

This blog post is from Bkjia blog ^_^ Hua. If you have any questions, go to the blog page for an interactive discussion!

Blog: http://lining.blog.51cto.com/7879843/1396044

NAT basic IP address conversion Principle

In general, the NAT address translation process is the conversion process between the "local address" and "Global Address", whether the packets are sent from the internal network to the external network, or from the external network to the internal network. The difference is that the network corresponding to the local address and global address is different, and the source and destination addresses of data packets are different. Next, we will use an experiment to implement NAT translation, and use a local host to access external servers and implement DNS conversion.

Tutorial ideas:

As a local host, pc0 and pc1 have their own local ip addresses. when accessing servers on the public network, you must first convert these two local ip addresses into major ip addresses for public network communication, currently, their internal Global ip addresses are 192.168.1.1 and 192.168.1.2, and their destination ip addresses are 192.168.2.1 and 192.168.2.2. For other configurations, see the procedure.

The experiment topology is as follows:

Note:

1) Select a route with an expansion slot and add a serial slot

2) There is a serial DCE line with a clock when connecting the line. Connect the end first and use the end as the DCE end. The clock frequency is required.

Tutorial steps:

1) configure the device address and enable the routing Port

PC0

PC1

R0:

Router> en

Router # conft

Enterconfiguration commands, one per line. End with CNTL/Z.

Router (config) # intf0/0

Router (config-if) # ipadd 10.0.0.1 255.255.255.0

Router (config-if) # nosh

% LINK-5-CHANGED: Interface FastEthernet0/0, changed state to up

% LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up

Router (config-if) # ints1/0

Router (config-if) # ex

Router (config) # ints1/0

Router (config-if) # ipadd 172.16.1.1 255.255.255.0

Router (config-if) # clockrate 1200 (because of our online R0)