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的攻击。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 - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - 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 - ODR
P - periodic downloaded static route
Gateway of last resort is not set
C 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 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 reject
permitSpecify packets to forward
remarkAccess list entry comment
R1(config)#access-list 1 permit ?
A.B.C.DAddress to match
any Any source host
host A single host address
R1(config)#access-list 1 permit 192.168.1.0 ?
A.B.C.DWildcard 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 translation
outsideOutside address translation
pool Define pool of addresses
R1(config)#ip nat pool ?
WORDPool name
R1(config)#ip nat pool david ?
A.B.C.DStart IP address
R1(config)#ip nat pool david 200.1.1.3 ?
A.B.C.DEnd IP address
R1(config)#ip nat pool david 200.1.1.3 200.1.1.3 ?
netmaskSpecify the network mask
R1(config)#ip nat pool david 200.1.1.3 200.1.1.3 netmask ?
A.B.C.DNetwork 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 ?
sourceSource address translation
R1(config)#ip nat inside source ?
list Specify access list describing local addresses
staticSpecify static local->global mapping
R1(config)#ip nat inside source list 1 ?
interfaceSpecify interface for global address
pool Name pool of global addresses
R1(config)#ip nat inside source list 1 pool ?
WORDName pool of global addresses
R1(config)#ip nat inside source list 1 pool david ?
overloadOverload 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 statistics
translationsTranslation 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
ProInside 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
R1#show ip nat translations //来自1.2和1.3的主机访问
ProInside 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 200.1.2.2:80 200.1.2.2:80
R1#show ip nat translations
ProInside 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 200.1.2.2:80 200.1.2.2:80
R1#
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 - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - 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 - ODR
P - periodic downloaded static route
Gateway of last resort is not set
S 192.168.1.0/24 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>ipconfig
IP Address......................: 192.168.1.2
Subnet Mask.....................: 255.255.255.0
Default Gateway.................: 192.168.1.1
PC>ping 200.1.2.2
Pinging 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=126
Ping 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 = 15ms
PC>
PC-WEB:
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