Packet Tracer 5.2实验(十五) 网络端口地址转换NAPT配置

一、实验目标

• 理解NAT网络地址转换的原理及功能；

• 掌握NAPT的配置，实现局域网访问互联网；

二、实验背景

公司办公网需要接入互联网，公司只向ISP申请了一条专线，该专线分配了一个公网IP地址，配置实现全公司的主机都能访问外网。

三、技术原理

• NAT将网络划分为内部网络和外部网络两部分，局域网主机利用NAT访问网络时，是将局域网内部的本地地址转换为全局地址（互联网合法的IP地址）后转发数据包；

• NAT分为两种类型：NAT（网络地址转换）和NAPT（网络端口地址转换IP地址对应一个全局地址）。

• NAPT：使用不同的端口来映射多个内网IP地址到一个指定的外网IP地址，多对一。

• NAPT采用端口多路复用方式。内部网络的所有主机均可共享一个合法外部IP地址实现对Internet的访问，从而可以最大限度节约IP地址资 源。同时，又可隐藏网络内部的所有主机，有效避免来自Internet的***。因此，目前网络中应用最多的就是端口多路复用方式。

四、实验步骤

实验拓扑

1、R1为公司出口路由器，其与ISP路由器之间通过V.35电缆串口连接，DCE端连接在R1上，配置其时钟频率为64000；

2、配置PC机、服务器及路由器接口IP地址；

3、在各路由器上配置静态路由协议，让PC间能相互ping通；

4、在R1上配置NAPT；

5、在R1上定义内外部网络接口；

6、验证主机之间的互通性。

R1:

Router>en
Router#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#host R1
R1(config)#int fa0/0
R1(config-if)#ip add 192.168.1.1 255.255.255.0
R1(config-if)#no shut%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up
R1(config-if)#exit
R1(config)#int s2/0
R1(config-if)#ip add 200.1.1.1 255.255.255.0
R1(config-if)#no shut%LINK-5-CHANGED: Interface Serial2/0, changed state to down
R1(config-if)#clock rate 64000
R1(config-if)#exit
R1(config)#
R1(config)#
R1(config)#
R1(config)#
%LINK-5-CHANGED: Interface Serial2/0, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial2/0, changed state to up
R1(config)#
R1(config)#ip route 200.1.2.0 255.255.255.0 200.1.1.2                           //配置静态路由
R1(config)#end
R1#
%SYS-5-CONFIG_I: Configured from console by console
R1#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGPi - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area* - candidate default, U - per-user static route, o - ODRP - periodic downloaded static routeGateway of last resort is not setC    192.168.1.0/24 is directly connected, FastEthernet0/0
C    200.1.1.0/24 is directly connected, Serial2/0
S    200.1.2.0/24 [1/0] via 200.1.1.2
R1#
R1#
R1#
R1#
R1#
R1#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R1(config)#int fa0/0
R1(config-if)#ip nat inside
R1(config-if)#exit
R1(config)#int s2/0
R1(config-if)#ip nat outside
R1(config-if)#exit
R1(config)#access-list ?  <1-99>     IP standard access list  <100-199>  IP extended access list
R1(config)#access-list 1 ?deny    Specify packets to rejectpermit  Specify packets to forwardremark  Access list entry comment
R1(config)#access-list 1 permit ?A.B.C.D  Address to matchany      Any source hosthost     A single host address
R1(config)#access-list 1 permit 192.168.1.0 ?A.B.C.D  Wildcard bits  <cr>R1(config)#access-list 1 permit 192.168.1.0 0.0.0.255 ?  <cr>R1(config)#access-list 1 permit 192.168.1.0 0.0.0.255                       //定义访问控制列表
R1(config)#ip nat ?inside   Inside address translationoutside  Outside address translationpool     Define pool of addresses
R1(config)#ip nat pool ?WORD  Pool name
R1(config)#ip nat pool david ?A.B.C.D  Start IP address
R1(config)#ip nat pool david 200.1.1.3 ?A.B.C.D  End IP address
R1(config)#ip nat pool david 200.1.1.3 200.1.1.3 ?netmask  Specify the network mask
R1(config)#ip nat pool david 200.1.1.3 200.1.1.3 netmask ?A.B.C.D  Network mask
R1(config)#ip nat pool david 200.1.1.3 200.1.1.3 netmask 255.255.255.0 ?  <cr>R1(config)#ip nat pool david 200.1.1.3 200.1.1.3 netmask 255.255.255.0
R1(config)#ip nat inside ?source  Source address translation
R1(config)#ip nat inside source ?list    Specify access list describing local addressesstatic  Specify static local->global mapping
R1(config)#ip nat inside source list 1 ?interface  Specify interface for global addresspool       Name pool of global addresses
R1(config)#ip nat inside source list 1 pool ?WORD  Name pool of global addresses
R1(config)#ip nat inside source list 1 pool david ?overload  Overload an address translation  <cr>R1(config)#ip nat inside source list 1 pool david overload ?  <cr>R1(config)#ip nat inside source list 1 pool david overload
R1(config)#end
R1#
%SYS-5-CONFIG_I: Configured from console by console
R1#show ip nat ?statistics    Translation statisticstranslations  Translation entries
R1#show ip nat translations                                                      //没有主机访问Web Server的时候，没有记录R1#
R1#show ip nat translations                                                      //有主机访问Web Server，产生记录Pro  Inside global     Inside local       Outside local      Outside global
tcp 200.1.1.3:1026     192.168.1.2:1026   200.1.2.2:80       200.1.2.2:80R1#show ip nat translations                                                      //来自1.2和1.3的主机访问
Pro  Inside global     Inside local       Outside local      Outside global
tcp 200.1.1.3:1026     192.168.1.2:1026   200.1.2.2:80       200.1.2.2:80
tcp 200.1.1.3:1025     192.168.1.3:1025   200.1.2.2:80       200.1.2.2:80R1#show ip nat translations
Pro  Inside global     Inside local       Outside local      Outside global
tcp 200.1.1.3:1026     192.168.1.2:1026   200.1.2.2:80       200.1.2.2:80
tcp 200.1.1.3:1027     192.168.1.2:1027   200.1.2.2:80       200.1.2.2:80
tcp 200.1.1.3:1025     192.168.1.3:1025   200.1.2.2:80       200.1.2.2:80
tcp 200.1.1.3:1024     192.168.1.3:1026   200.1.2.2:80       200.1.2.2:80R1#

R2:

Router>en
Router#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#hostname R2
R2(config)#int fa0/0
R2(config-if)#ip add 200.1.2.1 255.255.255.0
R2(config-if)#no shut%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up
R2(config-if)#exit
R2(config)#int s2/0
R2(config-if)#ip add 200.1.1.2 255.255.255.0
R2(config-if)#no shut%LINK-5-CHANGED: Interface Serial2/0, changed state to up
R2(config-if)#
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial2/0, changed state to up
R2(config-if)#
R2(config-if)#
R2(config-if)#exit
R2(config)#ip route 192.168.1.0 255.255.255.0 200.1.1.1
R2(config)#end
R2#
%SYS-5-CONFIG_I: Configured from console by console
R2#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGPi - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area* - candidate default, U - per-user static route, o - ODRP - periodic downloaded static routeGateway of last resort is not setS    192.168.1.0/24 [1/0] via 200.1.1.1
C    200.1.1.0/24 is directly connected, Serial2/0
C    200.1.2.0/24 is directly connected, FastEthernet0/0
R2#
R2#
R2#
R2#

PC1:

Packet Tracer PC Command Line 1.0
PC>ipconfigIP Address......................: 192.168.1.2
Subnet Mask.....................: 255.255.255.0
Default Gateway.................: 192.168.1.1PC>ping 200.1.2.2Pinging 200.1.2.2 with 32 bytes of data:Reply from 200.1.2.2: bytes=32 time=15ms TTL=126
Reply from 200.1.2.2: bytes=32 time=16ms TTL=126
Reply from 200.1.2.2: bytes=32 time=16ms TTL=126
Reply from 200.1.2.2: bytes=32 time=15ms TTL=126Ping statistics for 200.1.2.2:Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:Minimum = 15ms, Maximum = 16ms, Average = 15msPC>

PC-WEB: