Detailed explanation of nat/napt address translation (internal and external network communication) technology [Huawei ENSP]

One . Preface

We've solved it before ,DHCP,VRRP,MSTP,OSPF Demand. , Let's solve the need of internal and external network communication ：

11. Think about how to realize when intranet users need to access the Internet

First, let's take a look at our current topology ：

Now the demand is that no Department of our intranet can communicate with the external network .
The effect is as follows ：
A Department can ping Extranet PC machine ：

Look at the bag we caught ：
our A Department equipment ip The address is ：192.168.10.123, And the message we caught showed ：119.119.119.1, This is our NAT/NAPT technology , Will be intranet ip First map to a ip Address to communicate with the external network .

Two . Experimental process

The experimental process is quite simple ：
First go to the core layer router

Go to G0/0/0 port , Configure ports first ip：

ip address 119.119.119.1 255.255.255.0

And then configuration NAPT：

nat outbound 2000

configured NAPT after , We need to configure ALC：
Get into 2000

acl number 2000

Configuration rules ：

rule 5 permit source 192.168.10.0 0.0.0.255
rule 10 permit source 192.168.20.0 0.0.0.255
rule 15 permit source 192.168.30.0 0.0.0.255

Come here , Our core layer router has been configured .

next step ： Configure internet router ：

Into the first E0/0/0 port , Configure it IP Address ：

ip address 119.119.119.119 255.255.255.0

Get into Ethernet0/0/1 port , To configure ip Address ：

ip address 172.16.0.254 24

Finally, configure the device linked to the Internet ip：

The configuration is as follows ：

ping Gateway test ：

Intranet A department ping Extranet equipment ：

Fulfill demand ！

summary ：
NAPT It is not easy to break the package , Than NAT The applicability of .