路由器nat

R1：

<H3C>sys

[H3C]sysname R1

[R1]int LoopBack 0

[R1-LoopBack0]ip address 2.2.2.2 32

[R1-LoopBack0]quit

[R1]router id 2.2.2.2

[R1]vlan 10

[R1-vlan10]quit

[R1]vlan 20

[R1-vlan20]quit

[R1]int vlan 10

[R1-Vlan-interface10]ip address 192.168.10.1 24

[R1-Vlan-interface10]quit

[R1]int vlan 20

[R1-Vlan-interface20]ip address 192.168.20.1 24

[R1-Vlan-interface20]quit

[R1]int gi 5/0

[R1-GigabitEthernet5/0]port link-mode bridge

[R1-GigabitEthernet5/0]port link-type access

[R1-GigabitEthernet5/0]port access vlan 10

[R1-GigabitEthernet5/0]quit

[R1]int gi 5/1

[R1-GigabitEthernet5/1]port link-mode bridge

[R1-GigabitEthernet5/1]port link-type access

[R1-GigabitEthernet5/1]port access vlan 20

[R1-GigabitEthernet5/1]quit

[R1]int gi 0/1

[R1-GigabitEthernet0/1]description <connect to ISP>

[R1-GigabitEthernet0/1]ip address 202.1.100.2 28

[R1-GigabitEthernet0/1]quit

NAT配置：

[R1]acl basic 2000

[R1-acl-ipv4-basic-2000]rule 0 permit source any

[R1-acl-ipv4-basic-2000]quit

[R1]nat address-group 1

[R1-address-group-1]address 202.1.100.3 202.1.100.5

[R1-address-group-1]quit

[R1]int gi 0/1

[R1-GigabitEthernet0/1]nat outbound 2000 address-group 1 no-pat

[R1-GigabitEthernet0/1]quit

[R1]ip route-static 0.0.0.0 0.0.0.0 202.1.100.1

ISP：

<H3C>sys

[H3C]sysname ISP

[ISP]int gi 0/1

[ISP-GigabitEthernet0/1]description <connect to R1>

[ISP-GigabitEthernet0/1]ip address 202.1.100.1 28

[ISP-GigabitEthernet0/1]quit

[ISP]int gi 0/0

[ISP-GigabitEthernet0/0]description <connect to PC-3>

[ISP-GigabitEthernet0/0]ip address 202.103.224.254 24

[ISP-GigabitEthernet0/0]quit

测试：

所有PC都填写上IP地址、子网掩码、默认网关

PC-4和PC-5能PING通PC-3

查看NAT的转换情况及会话清单：